Study: Only Wealthiest and Best Educated Benefit from Mediterranean Diet

In a noteworthy first, a large-scale study in Italy has found that following the so-called Mediterranean diet reduced heart disease risk only for those in top of the educational and income cohorts. Even more disconcerting, the researchers pushed the data around and didn’t find strong explanations for what might have caused the disparity in results.

We’ll discuss the study, High adherence to the Mediterranean diet is associated with cardiovascular protection in higher but not in lower socioeconomic groups: prospective findings from the Moli-sani study in more detail below. I encourage the medically and statistically minded to read the study in full and add their views.

We pointed out in 2007 that socioeconomic status played a big role in health outcomes, and even more so in countries with high degrees of economic disparity. So one has to wonder to what degree the stress of being poor, and of increased precariousness for older low and middle income individuals (the people selected for this study were over 35 and were in less than perfect health) offset the benefits of a good diet, meaning even though the Mediterranean diet may not have led to better results, they would have been worse off had they not followed it.

The study was large scale, starting out with over 24,000 participants and winding up with nearly 19,000 after various screens were applied, like missing data and implausible inputs. Subjects provided extensive information on health indicators, and in many ways, the diet reporting was detailed (for instance, it scored the variety of fruit and vegetable consumption as well as “healthier” versus less healthy veggie and protein cooking methods, as well as the level of organic food consumption). The findings were controlled for age, smoking level, body mass index, and amount of physical activity.

They also scored the participants’ diets on “food antioxidant content.” But there were some odd gaps, like looking only at whether the participants ate whole grain bread as the measure of whole grain consumption. Anyone who had made “whole grain” bread will tell you it still consists primarily of white flour, plus looking only at bread would omit those who ate oatmeal or other cooked cereals (where does polenta fit in the “healthy grain” spectrum?) Nevertheless, the effort to score the diets on a more granular basis looked sound.

The researchers divided participants into three socioeconomic groups based on income and educational levels.

The social stratification impact was strong enough that the authors flagged it as a “key message:”

Cardiovascular advantages associated with the Mediterranean diet are confined to high socioeconomic status individuals.

The International Journal of Epidemiology article also highlighted that there were “inequities” in “diet-related behaviours and nutrient intake”. However, if you read the piece, you can infer that the authors are scratching their heads a bit, in that the differences in eating behaviors that they observe by socioeconomic group don’t seem to be sufficient to add up to the difference in results.

However, the biggest disparity, and this could potentially be significant, is that the best-off ate more fish and less meat. However, the meat they did eat was prepared more often in the methods the researchers deemed to be less healthy, namely frying or grilling as opposed to stewing or boiling. The highest status groups ate more organic food, but since many studies have found that organic foods don’t contain more nutrients, they seemed unwilling to attribute much significance to that.1 Conversely, less well off participants used the “less healthy” cooking methods more often on veggies. Higher income people ate more whole grain bread; the less well off groups had more variety in their fruits and vegetables and consumed a smidge more of the mono and poly-unsaturated fatty acids.

The top income group also ate more “nutritionally dense” foods.2:

Dietary intake of polyphenols, antioxidants, fibre and indicators of TAC [total antioxidant capacity] were all increased in the higher income group as compared with the lowest.

Lambert had an interesting theory: that olive oil is often adulterated, and therefore the lower income groups might not be getting the “monounsaturated fatty acid” benefit that the researchers thought they would from their reported oil oil consumption. I doubt that would swing the results but it could be a contributing factor.

The authors admit they are groping for explanations:

On the basis of our results and by accounting for all the limitations inherent to our approach, we suggest that at comparable levels of adherence to the MD, higher SES groups actually select foods with increased nutritional value as those higher in antioxidant content or capacity, and are more keen on reporting a larger variety in fruit and vegetable consumption, thus obtaining more adequate intake of essential nutrients. Such nutritional gaps may partly explain the observed socioeconomic pattern of protection derived from apparently similar scores of adherence to the MD. Of note, the interaction between diet and SES on CVD health outcomes was found both for cultural (education) and financial resources (income), likely indicating that healthier choices are driven either by a good set of knowledge and skills or greater financial resources.

In light of our findings, we speculate that standard dietary scores, although useful and valid parameters to quantify the adherence to the Mediterranean diet, may not fully capture the complexity of this diet, leaving out a number of additional dietary details mainly related to the quality of the products. If so, we would be dealing with a methodological limitation which may be overcome by the use of other tools to better appraise the dietary behaviours of a given population.

Needless to say, this finding is intriguing but leaves a lot of questions unanswered. Again, the most likely hypothesis would seem to be that diet can’t explain the difference in results. The most likely non-diet factor would be stress, either overall or greater incidence of high stress events in the lower 2/3 groups played a role.

Is it possible that mere concerns about food safety could be a significant factor? More diet-conscious Americans are nervous, to the degree of neuroticism, about what they eat, so you get self-undermining behaviors like people drinking bottled water when it turns out sitting in plastic means the water picks up chemical nasties from the plastic. However, given how powerful placebo effects are, I wonder if better off-people are more confident in their food choices, like buying more organic food, and that helped contribute to these results.

Needless to say, this is an important indicator if disheartening indicator of yet another way those at the top of the heap come out ahead.
______

1 My view, consistent with that of a relative who had a healthy cooking venture and later coached health coaches, was that people in the US eat organic food to avoid things like pesticides and artificial hormones, and not because they think they have more “nutrients”.

2 The reason I am signaling some skepticism is “nutritional density” has become a fad in the US. While some foods clearly have more nutritional value than others, such as dark leafy greens versus, say cucumber, the “supernutrient” fetish implies that you can get enough nutrients without supplementation. The USDA said in 1938 that soils were so depleted that it was no longer possible to get enough nutrients from one’s diet. It’s also pretty much impossible for women to get enough calcium on a caloric intake that won’t make them overweight (note this presumably was possible when women were eating a lot more because they were engaged in strenuous physical activity on a regular basis, like helping out in the fields, beating rugs out, and churning butter by hand). So while there is some merit in the line of thinking, it’s been overhyped.

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105 comments

  1. it should be obvious

    Frying and grilling is a faster way of cooking that also requires less water, the authors of the study could have checked the cost of water on a median income family budget.

    Cucumber, tomato, oranges, onions, carrots, require very little water in order to be prepared.

    Mind you none of the mediterranean countries are anywhere near self-sufficient in food, They prefer to sell wine to those who have bread and beer. I jest, it’s all inventory accounting control fraud.

    Yes, olive oil is expensive and the quality isn’t great for the lower classes. As a matter of fact in order to get a better price the poor have to spend a greater relative amount of their budget.
    I’m sure you’ll find that in quantities the exports surpass the comsumption in the home market while in cashflow the relation is reversed for greens and other products which are supposed to be a natural monopoly of the region..

    1. Yves Smith Post author

      You ignore the point that there’s no evidence on how much the “less good” methods of cooking reduce nutrition value v. the “better” ones, let alone for veggies v. meats. So your finger-wagging is misplaced.

      And aside from tomatoes, where cooking increases lycopene at the expense of other nutrients, cooking in general reduces nutritional content.

      1. diptherio

        As an aside, there’s a great book called Eating on the Wild Side that collects all of the recent data from nutritional scientists on cooking methods and nutrient content.

      2. Stephen Rhodes

        And aside from tomatoes, where cooking increases lycopene. . .

        Not to mention liberating beta-carotene from raw carrots.

  2. Societal Illusions

    haven’t read the study yet but my initial thought after reading the article is around stress.

    There is a certain level of security as a result of financial abundance, which could reduce stress levels. Financial hardship or difficulty could increase stress levels.

    It’s clear stress alone can lead to poor health results so perhaps that could be causative.

    1. diptherio

      Yes, I think the Whitehall study of British social servants and the work of Robert Sapolsky and other primatologists studying the effects of stress explain the results. The relationship between social position, stress, and health outcomes is, imho, very important but rarely addressed — especially in studies like this that assume it’s not a factor from the outset.

      1. Anon

        Yes, this is a very relevant comment. Stress AND biological inflammation of any kind (dental disease, broken bones, repetitive viral attacks. etc) can encourage the body to produce LDL cholesterol and lead to greater incidence of heart damage.

        My dentist (30 years ago) implored me to do a better job brushing as it was known then that oral health was essential to reducing cardiac issues.

        I think finding a specific cause for heart disease is likely difficult; since every body is different.

    1. Yves Smith Post author

      I’m not sure that makes much difference unless you can argue that they are genetically different from other people. In fact, the advantage of using people from one area is that it removes other types of noise, like the poor people potentially being in urban areas, so traffic sounds (disrupted sleep patterns) and worse air in cities could confound the results. And it means that everyone in theory ought to have been eating largely similar quality produce, meats, and fish, absent the “organic” component. But per the olive oil issue, there is still the potential for quality differences on other axes.

      1. PKMKII

        It does indicate that it would be worthwhile to replicate the study in a different environment/location. Perhaps differences in the results with follow-up studies versus the original could show why there’s a socioeconomic split.

  3. PlutoniumKun

    Given that so many studies of the mediteranean diet tended to focus on poorer rural dwellers in places like southern Italy or Greek islands who often have very long lives I would be dubious that simply poverty stress is an explanation, unless the study was looking at urban populations who might have a very different diet due to buying everything in supermarkets rather than growing their own.

    I recall years ago reading studies of Italian immigrants in parts of the US who had similarly low rates of cardiovascular disease than their forebears, despite having out of necessity swapped products like olive oil for bacon fat in their recipes, and hugely upping the meat content of their diets – it was attributed at the time I think to closer family relations. These were among the first studies I think which questioned the ‘fats are bad’ obsession of the 1970’s and 80’s.

    I suspect the key issue is the sourcing of the food products. There is a world of difference nutritionally between a ‘wholemeal bread’ found in a typical discount supermarket and the ‘wholemeal bread’ bought from a traditional, or a modern ‘artisan’ breadmaker. They look superfically the same, but they have a vastly different composition. Even dried pastas can have a very different composition, down to using different types of wheat grain (in my experience, better off Italians are extremely fussy about specific brands of basic products like dried pasta and tinned tomatoes). A visiting Milanese friend insisted she would not cook for me unless I had a specific brand of pasta (which cost twice as much as regular pasta) in my kitchen. I did have to admit it tasted distinctly better – she said they used better quality wheat.

    So if I was to make a guess at the reason for this, it is that better quality products are not just marketing nonsense – organic and genuine ‘artisan’ foods do have more good stuff and (perhaps more importantly) less bad stuff in their composition.

    1. yan

      As far as the Greek Islands go, and most sensationalist articles always focus on Ikaria, the thing is “poverty stress” is not a thing. Although “poor” by any economic meaure, I would say the stress part is not there. This might be changing now that islanders are having their “winter wages” cut by the state. Up to now, if you worked in the tourism industry (most do in some shape or form) you would get a wage supplement (if you paid your social security dues) during the off months when tourism in non existent. Life can be cheap on the islands in the winter. Also, most people own land and cultivate it year round, or a family member does for basic foodstuffs (potatoes, greens, grapes, beans, etc).
      About the water issue: although scarce, I have never heard of anybody trying to “optimize” their cooking for water (in the north mediterranean).

      1. Kay McDonald

        Without reading the study, I’d be most interested in the BMI correlations and lifestyle factors of the participants.

        When one considers longevity areas and studies, a few things seem to predominate:

        growing your own food; sourcing eggs and meats from naturally grazed and grass/bug-fed livestock and birds – hugely important for the quality fats and nutrients contained; strong social connections; and constant movement due to work -into old age- including gardening, household tasks, and walking everywhere instead of driving a car everywhere; breathing clean unpolluted air, and drinking pure unpolluted water. Most of these studies finding longevity areas or “blue zones” such as Ikaria did not discover enclaves of rich people, quite the opposite. Furthermore, perhaps they have avoided unnecessary medical procedures and have not had to punch a clock for their daily work. They have lived in the outdoors, in Nature, instead of on concrete. Lifestyle is as important as what we eat. Obesity is a leading cause of death and leads to chronic diseases like diabetes, cardiovascular disease, and cancers. Constant movement lifestyle and a diet in moderation help to prevent obesity.

        The new focus on longevity is in South Korean women and tries to put credit on kimchee. [see: https://www.ft.com/content/63154cec-fa75-11e6-9516-2d969e0d3b65%5D

        As for the Mediterranean Diet, it makes a lot of sense, so I wouldn’t discredit it based on this new study. It advocates meat for flavor, low sugar intake, whole grains, and lots of (fresh, organic) fruits and vegetables.

    2. TheCatSaid

      Regarding different kinds of pasta, I have noticed my body feels very different depending on the quality of pasta. The cheapest generic brands are horrible–I feel like I’ve put filling sludge into my body. The Italian brands are much better and I don’t get slowed down by them. I’m sure they’re using very different varieties and qualities of wheat. And perhaps Italian soils are not as depleted as in some other places.

      IOW, all wheat is not the same, even if it’s “bad” refined white wheat.

      1. PlutoniumKun

        Italian pasta is made from durum wheat which by reputation is easier to digest than more modern varieties. Its possible cheaper pastas are made from other grains. Italian pasta (i.e. pasta made under Italian law) also has to be made from unleaved dough – most heavily processed wheat products leaven doughs to speed up production. Either of those could be reasons why your body prefers it.

      2. Lord Koos

        There is also the fact that American farmers use Monsanto’s Roundup, which contains the poison glyphosate. It is banned in the EU. Some people think that the gluten intolerance that so many people in the US report, is actually the glyphosate in the wheat. Others say it’s because the wheat so hybridized that bears little resemblance to wheat grown 60 years ago.

    3. ginnie nyc

      Re: Italian immigrants in the US and cardiovascular disease – the low rates of cardio disease persist only through the 3rd generation, at most. After that, the rates begin to ascend, as diet more closely mimics the broad ‘American’ mainstream, looser family ties (relocation for work), and stressful sedentary jobs.

  4. K Tree

    Digestion is a complex process, with many more factors involved that determine whether or not the nutritious components of a food are absorbed into the body.

    The microflora in the gut can exert a large influence over what parts of a food become available. These colonies can be impacted by a huge range of factors, stress and use of antibiotics being two significant ones. I’d gamble that the better offs have less infections, and if they do have them, they are not put on courses of the same antibiotics. The microflora in their intestines are less impacted and better able to process whatever they eat. They also likely take more time to consume their meals, and the chewing process itself might increase the availability of different nutrients.

  5. MoiAussie

    Not mentioned here, the study only tracked people from 2005 to 2010. It’s likely that the modern version of the Mediterranean diet is significantly less beneficial than the diet of 50 years ago, as PK alludes to above, particularly for members of lower socio-economic strata. Other aspects of 21st century life probably contribute negatively too.

    Someone mentioned stress – the study period also coincides with the GFC. So maybe one should hypothesize that not even a Mediterranean diet can adequately protect people from financial immiseration and other consequences of the crash. Or the return of Berlusconi.

  6. WobblyTelomeres

    Anyone who had made “whole grain” bread will tell you it still consists primarily of white flour

    This is not so. “Many” or even “Most”, perhaps. Certainly not “Anyone” (All). I started making my own bread 8 years ago and use only King Arthur whole wheat flour.

    1. a different chris

      Well that’s not what most recipes I have seen say. Often 2/3 white vs 1/3 whole wheat.

      I suspect it’s a modernization for today’s tastes, and I credit you for avoiding it.

      1. WobblyTelomeres

        Flour, water, a tablespoon of yeast (proofed), a tablespoon of sugar or honey, no salt, no kneading (arthritis), just let it sit overnight and bubble away, then toss it in the oven for 30 minutes. Sometimes, I substitute oatmeal for some of the flour, or mash up a potato and stir it in if there is one boiled and hanging about in the fridge, or grind up some flax seed and stir that in. Always cheaper than store bread. Always better than store bread.

        I avoid regular flour as I’m on the Ornish diet. A diagnosis of atherosclerosis will do that to ya.

  7. craazyman

    The lower income people probably don’t even go to the Mediterranean very much but the wealthier people hit the beach in Italy probably a lot and eat in good, healthy restaurants on vacation.

    It’s healthy if you go to the ocean and swim in the sea — as long as you’re not attacked by a shark that is. I bet the Pacific diet in LA or San Diego would show the same result. If you can hit the beach at Malibu or The Wedge at Newport rather than work your 3 jobs it’s probably healthy. No surfing in the Med though, but that’s a small problem if you’r enot a surfer.

    1. Anon

      …and the risk of shark attack in the Mediterranean Sea is 10x’s LESS than in other parts of the world.

  8. Kevin Smith

    There is A LOT of corruption in Italy, and A LOT of illegal dumping of poisons and toxins, in particular in southern Italy.

    Could be that the well off know this, and are careful to purchase only food with a good provenance.

    1. paul

      There’s a good scene in ‘Gomorrah’ pertaining to this:

      Franco provides a low-cost toxic waste disposal service that allows northern industrialists to dispose of materials like chromium and asbestos in the countryside of southern Italy…….
      Franco and Roberto meet a family of farmers who, desperate to extinguish their debts, decide to allow the burial of chemical substances in their countryside. An elderly farmer gifts Roberto a basket of peaches, but Franco later tells him to throw them away because they are contaminated.
      Roberto then decides to quit his job and tells Franco he cannot bring himself to poison the earth, to which Franco says that he shouldn’t think he is the better man, because thanks to the actions of people like them Italy was able to enter the European Union, solving problems others had caused.
      Roberto walks alone on a desolate countryside road.

      1. Ned

        i.e.
        Buffalo mozzarella, made in Campana, adulterated by dioxin, the most toxic chemical substance ever. Eat that stuff and you might as well consume Fukushima farmed fish.

        Remember, the Japanese export food to the U.S. that they won’t allow to be sold in Japan. There is no safe dose of dioxin or radiation.
        Italian food is labeled as to regional origin, so there is some choice and control for the informed and curious. Japanese food is not. Anyone who cares about their health will boycott Japanese exported foods forever.

        1. Lord Koos

          I can’t speak to all Italian foods, but the Italian olive oil market is known to be corrupt and fraudulent, so even if it is designated by region, that doesn’t mean you’re getting what is indicated on the label.

        2. vidimi

          i wasn’t aware of mozza di buffala being contaminated. i don’t eat it often, but i do indulge occasionally.

        1. Outis Philalithopoulos

          Matteo Saviano wrote a famous book, Gomorra, on new developments in the Italian underworld, focusing not on the (Sicilian) mafia but on the more corporate camorra (in Campania). Subsequently it was adapted into a TV series. The book certainly discusses the issue of waste disposal at length, but I don’t remember off the top of my head if this passage is in the book or if it is instead a dramatization from the series.

  9. begob

    On adulterated olive oil – I’m in the UK and regularly use light olive oil to make mayonnaise with an electric blender, but some brands don’t emulsify. I assume these are blended with vegetable oil, which could be positively harmful owing to inflammatory omega 6 overload.

    1. Vatch

      This is a genuine problem in many places. People have analyzed the polyphenol content of many olive oil brands, and some of the information is freely available on the web. The first link has a large number of brands, and it can be sorted by various component chemicals:

      https://www.oliveoiltimes.com/phenolic-compounds-olive-oils-bought-california

      Here’s a free summary of some data that’s behind a paywall:

      http://www.rvnetwork.com/index.php?/topic/126275-latest-extra-virgin-olive-oil-brand-tests-by-consumerlabcom/

      General information:

      http://www.lifeextension.com/Magazine/2016/9/Is-Your-Olive-Oil-Counterfeit/Page-01

    1. yan

      I woudl say that being a vegan is more of a fad than eating a traditional diet that has been in place for over a thousand years.

    2. Vatch

      If one chooses to be a vegan, it is absolutely crucial to take a vitamin B-12 supplement, because there are no reliable plant sources of this essential vitamin (maybe sourdough bread and sea weed, but those are controversial). A vitamin K-2 supplement is probably also a good idea. Everyone should be sure to get enough vitamin D, whether vegan or not.

      1. weaver

        B12 deficiency is extremely rare even among strict vegans, in any case it would take at least 3-5 years. We make B12 as do other animals, just low enough in our digestive tract that not all of us may get sufficient use of it. It’s a hormone as is “vitamin D”. If you garden or buy non-industrially washed veggies you’re likely fine. Taking 5-10 mg a day is more than enough to prevent an unlikely problem. Vitamin supplements as a whole are a bad idea and no substitute

        1. Vatch

          I disagree, but I will point out that I am not a medical professional. Some links:

          http://www.aafp.org/afp/2011/0615/p1425.html

          In 1994, the Framingham Heart Study reported the prevalence of vitamin B12 deficiency, as defined by a serum vitamin B12 level less than 200 pg per mL and elevated levels of serum homocysteine, methylmalonic acid, or both, to be 12 percent among 548 community-dwelling older patients.

          http://ajcn.nutrition.org/content/89/2/693S.full

          The prevalence of deficiency (serum vitamin B-12 < 148 pmol/L) varied by age group and affected ≤3% of those aged 20–39 y, ≈4% of those aged 40–59 y, and ≈6% of persons aged ≥70 y. Deficiency was present in <1% of children and adolescents but was ≤3% in children aged 20% of those >60 y. Plasma MMA concentrations were markedly higher after age 60 y. Of >1600 elderly (age ≥60 y) California Hispanics in the Sacramento Area Latino Study on Aging (SALSA), 6% had plasma vitamin B-12 in the range of deficiency and an additional 16% had marginal status, with evidence of further decline in plasma vitamin B-12 with age (6). The prevalence of vitamin B-12 deficiency (serum B-12 ≤ 150 pmol/L) increased substantially after age 69 y in 3 UK surveys (combined n = 3511); it affected about 1 in 20 people aged 65–74 y and at least 1 in 10 of those aged ≥75 y (7, 8).

          The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature. (abstract only):

          https://www.ncbi.nlm.nih.gov/pubmed/24667752

          The deficiency prevalence among infants reached 45%. The deficiency among the children and adolescents ranged from 0 to 33.3%. Deficiency among pregnant women ranged from 17 to 39%, dependent on the trimester. Adults and elderly individuals had a deficiency range of 0-86.5%. Higher deficiency prevalence was reported in vegans than in other vegetarians. Thus, with few exceptions, the reviewed studies documented relatively high deficiency prevalence among vegetarians. Vegans who do not ingest vitamin B12 supplements were found to be at especially high risk. Vegetarians, especially vegans, should give strong consideration to the use of vitamin B12 supplements to ensure adequate vitamin B12 intake. Vegetarians, regardless of the type of vegetarian diet they adhere to, should be screened for vitamin B12 deficiency.

    3. kareninca

      I was a vegan for 19 years, and only ate “health” food; all whole grains and lots of vegetables. My blood sugar got too high; A1c was 5.7. Adding yogurt and cheese brings it to 5.5. If I eat mostly dairy products (low carb), it is 5.2. I wish I could be vegan for ethical reasons, but I am not willing to become diabetic. Anyone who tries being vegan should keep a close eye on his/her blood sugar levels.

  10. Mark

    The health and mortality effects of socioeconomic position are well documented (see Marmot’s The Status Syndrome and The Health Gap for reviews of work that goes back about 40 yrs or so). The authors of the study did risk adjust their data for measures of socioeconomic status (education and income). The study uses self reported data which is a well known problem. The authors attempted to adjust for this as best they could by removing obviously wrong reports (for example, removal of reports with “implausible energy intakes”). The authors do a good job of enumerating this and other kinds of problems in the section “Strengths and limitations of this study”.

    Now for my buts:

    As with every study of this type that I know of, the absolute risk reductions are quite small: 0.35 – 0.4% for those with higher income, 0.9% for those with higher education level. I could not find data for all cause mortality which, in my view, is the most important number. Perhaps after longer follow up in the next paper?

    Certainly the authors met criteria for statistical significance (or the paper wouldn’t have been published) but given the small absolute effect and the problems associated with self-reported data are we not mistaking statistical significance for actual significance?

    1. reslez

      Well, if the study is credible it has “actual significance” in that the Mediterranean diet didn’t live up to its hype. They didn’t find a protective effect from it — any effect was too small to be detected. We know from other studies and basic census data that high SES does have a real and meaningful protective effect. In the US it’s worth almost a decade of lifespan.

      1. Emma

        Agree Mark. I think it limits their analysis. One of my major reservations about this study too is that it apparently entailed random enrollment via city registrars along with the multi-stage sampling. With self-reporting subjects, there is definitely a greater risk questions were misinterpreted or intentionally answered incorrectly for example.This all increases the risk for over-generalized conclusions.

    2. Yves Smith Post author

      I agree that focusing on mortality effects for only one set of disease factors, as in looking only at heart disease and stroke risk, is misguided. But there also wasn’t a control group for this study, which seems odd. One would have a lot better knowledge of what if any impact following this diet had if you saw what happened among people who didn’t follow it.

      Another possibility is that despite the size of the group, enough people lied about their degree of adherence to skew results. It doesn’t make clear how often they asked the subjects to report what they ate. More frequent reporting would give more confidence in the integrity of the data.

      The study reports no other assessment of health results at the end of the period:

      Primary fatal and nonfatal incident cases of CHD (unstable angina, myocardial infarction, coronary revascularization and sudden death from unspecified cardiac event) and cerebrovascular disease which occurred in the cohort during follow-up were ascertained by linkage of the study cohort to the hospital discharge files and to the regional Registro Nominativo delle Cause di Morte (ReNCaM) registry and death certificates (Istituto Nazionale di Statistica (ISTAT) form), by using the International Classification of Diseases, ninth revision (ICD-9). For CHD, ICD-9 codes 410–414 and/or reperfusion procedure (ICD-9 codes 36.0–36.9) and for cerebrovascular disease, ICD9 codes 430–432, 434, 436–438 or procedure codes for carotid revascularization (ICD 9 code 38.12) were considered.

      Suspected CHD deaths were identified when ICD-9 codes 410–414 or 798 and 799 were reported as the underlying cause of death or codes 250, 401–405, 420–429 as the underlying cause of death, associated with codes 410–414 as a secondary cause of death. Suspected cerebrovascular deaths were identified when ICD-9 codes 430–438 were reported as the underlying, antecedent or direct cause of death. All events were validated using procedures of the American Heart Association (AHA), World Heart Federation (WHF), European Society of Cardiology (ESC), Centres for Disease Control (CDC) and National Heart, Lung, and Blood Institute (NHLBI) for epidemiology and clinical research studies.16

      I didn’t see them do any other end of diet period assessment of factors that might have affected heart attack or stroke risk, like changes in blood pressure.

      It may be that if the Mediterranean diet is helpful, you have to adhere to it for a long period of time to get any noteworthy benefit, that two years isn’t/is barely enough.

      1. Mark

        These problems are inherent (imho) in most if not all human nutrition studies. They are very difficult to do and are trying to suss out small effects. Hence one often finds studies done to the best of the researchers abilities getting opposite effects.

        It’s always been curious to me that studies of statins for primary prevention of CVD also show almost exactly the same small absolute effects (absolute risk reductions on the order of 0.3 – 0.5%). I suppose the one difference is that these effects have been reproduced numerous times (the most recent Cochrane Review of statins found, if I remember correctly, 15 studies that met their quality criteria). Also curious to me is that these studies also have difficulty showing reductions in all cause mortality. The only study that showed such a reduction is the the Jupiter trial which, in my view, has a lot of problems (I thought it should have been excluded from the Cochrane Review but I will admit that is something that reasonable people could disagree about.)

        1. Cojo

          The small absolute risk reductions in statin trials are probably due to the fact that cardiovascular disease is a complex multifactorial disease. Hence the back and forth with dietary guidelines inclusion dietary cholesterol recommendations. Statins are unlikely to help one individual, but are cost effective when dealing with a large population.

          1. Yves Smith Post author

            The latest “best thinking” on statins, which does not seem to have reached most MDs, is that it is beneficial only for people who have heart disease, and not those with supposed heart disease risk factors like high LDL cholesterol. BTW the new improved thinking also is that triglycerides are a much better heart disease risk indicator than cholesterol.

            1. Cojo

              For sure if one has heart disease a statin is critical to secondary prevention. I agree that save for specific individuals with genetic lipid disorders (very high ldl levels) pushing statins is more controversial. Triglycerides are a more sensitive market to metabolic disruptions seen with poor diets high in carbohydrates and processed foods and likely indicate a higher risk population (prediabetics). The American Heart Association tried to answer the primary prevention population most likely to benefit from statins with a risk calculator. However, there has been controversy as it tends to overestimate risk hence overtreating the population. There is no incentive to perform a new rigorous primary prevention trial due to costs so taking statins for primary is typically left as an individual choice. Most physicians I work with will not push statins in primary prevention unless a patient demands it or they have risk factors like diabetes.

  11. Steve

    There is so much fraud in the food system it makes it difficult to really categorize what people are really eating. Another big problem is that people are incredibly poor at accurately reporting what they really are eating or doing.

  12. justanotherprogressive

    I haven’t read the report yet – I’ll read it when I have more time, but there is a glaring omission here that you wouldn’t know about if you’ve never been dirt poor:

    The wealthy and well educated eat a greater variety of foods than do the poor. The poor depend on staples and eat the same foods over and over, something the rich and the well educated would consider very “gauche”…..

    And while the author does mention that the wealthy and well educated eat more fish, he doesn’t mention that they also eat more sea food. I never tasted lobster, crab, scallops, etc., until I was an adult. And as for fish, well for what it costs to buy a fillet that can feed two, a poor person can buy enough hamburger to feed eight. So, no fish any more isn’t a part of a poor person’s diet, although it used to be….and for those people who wonder why the poor don’t fish more? Well, to find fish, you have to take a day off and go out into the hills where the streams are clean – nice if you have the time and good transportation – kind of impossible if you don’t…..

    And the rich eat more spices. I went spice shopping the other day and was shocked at some of the prices……most of those lovely spices the wealthy and well educated add to their daily foods to make them taste better are just out of reach for the poor….

    So well it’s nice to compare “diets” like the Mediterranean Diet – they really are two different things to the rich and the poor. For the rich, it is a great variety of foods and flavors – for the poor, it is spaghetti……

    1. Vatch

      for the poor, it is spaghetti

      FWIW, tomato based spaghetti sauce is an excellent source of the valuable carotenoid lycopene. But in general, I think you make a good point about the value of variety in one’s diet, and that variety sometimes costs extra.

    2. steve

      That is a very sweeping generalization and I have never seen anything in my life to make me believe it. There is also nothing wrong with spaghetti as long as your sauce doesn’t come from a jar and you buy decent pasta, which is way cheaper than hamburger. Wealthy also people in the US eat out much more often and in my experience they basically eat one or two different things every time.

    3. Kay McDonald

      One woman made the news this past year for being poor and eating the same foods over and over, lacking a “great variety”. That woman was Emma Morano and she lived to be the oldest documented person, dying at age 117. She lived in the Piedmont region of Italy.

      Interestingly, she ate 3 eggs a day and didn’t eat many fruits and vegetables.

      I wrote about her here: [https://bigpictureagriculture.blogspot.com/2017/04/oldest-person-ate-3-eggs-day.html]

      1. Yves Smith Post author

        FWIW. one reader who teaches biochemistry to MD students, reported a while ago that the cholesterol level associated with the lowest all-factor death rate for women was 270.

      2. kareninca

        from your website:

        “She ate three eggs a day, two of them raw – for more than 90 years.
        She had chicken for dinner in the evening.
        She rarely ate fruits and vegetables.”
        “She ate her raw eggs by scooping them up with biscotti.
        For lunch she ate pasta with raw minced meat.
        For supper she had a glass of milk.
        At night she ate biscotti and hazelnut chocolates.
        Last of the day, she had several spoons of her home spiked grappa, infused in a wide-necked jar with seven sage leaves, herbs and a few grapes.
        Also, she believed in self-sufficiency and had a strong Catholic faith.”

        Raw eggs scooped up with biscotti??? Pasta with raw minced meat??
        You mentioned that she had strong longevity genes. I wonder what the main factor was in her case.

      3. craazyman

        Do you think if she’d eaten a healthy diet, like the Med diet, she’d have lived to 170?

        She could maybe have gone to Mars.

        Why not? After 160 years on Earth it might not be such a crazy idea.

    4. Yves Smith Post author

      Read the post. That is not what the study found and it looked specifically at that issue. The study was conducted in Italy where behaviors are different than in the US. The middle/lower income people ate a greater variety of fruits and vegetables than the well-off group.

  13. Steve Ruis

    Re “The USDA said in 1938 that soils were so depleted that it was no longer possible to get enough nutrients from one’s diet.” Wasn’t this around the time of the Dust Bowl and could that comment have been directed at that phenomenon? This is hard to believe this is the current situation seeing as how we get our foods from farther flung locations (grapes from South American, strawberries from Mexico, etc.)

    1. kareninca

      I can’t get enough magnesium through food, and I eat an incredibly “healthful” diet. If I don’t take a magnesium supplement, I get restless leg syndrome. If I take the supplement, the problem goes away immediately. I”m betting a lot of people are magnesium deficient; check out a (partial) list of the symptoms of magnesium deficiency:

      Agitation and anxiety
      Restless leg syndrome (RLS)
      Sleep disorders
      Irritability
      Nausea and vomiting
      Abnormal heart rhythms
      Low blood pressure
      Confusion
      Muscle spasm and weakness
      Hyperventilation
      Insomnia

  14. cojo

    I suppose to try and address these findings we should first look back to the original concept of the Mediterranean diet studied by Ancel Keys in the early 1960’s. This focused on food patterns of Crete, Greece, and southern Italy. Keys focused on the diet aspect due to the paradox of relatively high fat content of the diets compared to western diets, yet high longevity and low incidence of cardiovascular disease, and cancers. Although subsequent studies have reinforced the Mediterranean diet as being a significant contributor to these findings, other unique attributes of these specific groups likely had an effect. Namely, close knit communities with strong family ties, very active agrarian lifestyles, as well as typically living in isolated mountainous regions with associated lower levels of air and water pollution. My personal additions to this include that these specific populations also tended to come from poor regions without modern for the time health care and associated higher infant mortality likely contributing to a pre-selection of genetically healthier individuals making it to adulthood and thus old age.

    As for our recent study, looking at the methodology, other than not being able to measure the quality of food components taken in by individuals, I would suspect the other unmeasured variables that likely contributed to the unexpected findings were, as mentioned by others, stress, as well as exposure to pollution based on where you lived. It is well known that poorer neighborhoods tend to be located in areas with higher air, water, and noise pollution. However, even with these factors taken into account I would have hoped that healthier diet choices would be able to ameliorate some of these deleterious effects.

    When looking at population studies, table 1 is usually key to finding subtle differences in population groups. One variable that jumps out from Table 1 of the study is the proportion of men in each individual group, from 41.1% in the poor group to 44.2% in the intermediate group and 49.7% in the high income group. Cardiovascular disease tends to strike men earlier in age so this may account for some of the findings as the mean age of study participants was early 50’s, a time when proportionately more men would suffer from cardiovascular disease.

    Another is married couples vs non married tend to be higher in the higher income groups. Weight was lower in the poorer group, and hypertension and hypercholesterolemia were higher in the high income groups. Finally energy intake was also higher in the high income groups. These were all statistically significant with P values less than 0.05. These differences likely contribute to the slightly higher adverse cardiovascular event incidence noted in the High income groups in table 2. In essence I think you have a slightly higher cardiovascular risk group in the High income group which thus shows higher statistical difference from dietary influences like the Mediterranean diet.

    It’s subtleties like these that likely contribute to discrepant findings in medical research, and why people should not hang their hat on any one study finding. Although interesting, the study does not meet the gold standard of double blinded placebo controlled study, as it would likely be impossible to perform in this case. I sometimes wonder in this era of publish or perish, if researchers are looking for “gotcha” findings like socioeconomic or gender differences to get publicity for their work.

    1. Yves Smith Post author

      Aha, that is VERY helpful, and I missed that entirely. Yes, the male skew alone may make the difference and the other differences across the cohorts look germane too.

          1. cojo

            My statistics are a bit rusty, but I’m not sure they appropriately stratified for the other cofounders such as hypertension, hypercholesterolemia, age or BMI.

    1. Yves Smith Post author

      No, they controlled for that:

      The multivariable models were adjusted for sex, age, smoking status, education, household income, marital status, BMI (categorical), total physical activity (ordered quintiles), hypertension and/or hypercholesterolaemia at baseline, energy intake and consumption of eggs and potatoes.

      And as cojo pointed out just above, the lowest income group was less heavy than the wealthier one, which is also inconsistent with your theory.

  15. Jabawocky

    Looking at the study I note two points. The first is that Mediterranean diet, although the focus of the study, does not look that important for health outcomes. In contrast, income and education are strongly linked to cardiovascular risk, regardless of diet. I guess this is already well known. Although the interaction between diet and income is strictly speaking significant, it looks like a small effect. I always impress upon students not to confuse ‘significant’ with’important’: this is a powerful study with the potential to ascribe significance to small effects.

    I suggest one idea for the link: I wonder whether doctors, who are in the main educated and of reasonable means, more proactively treat people from higher income groups, perhaps because of unconscious bias, or perhaps because they are more likely to suspect the working class of malingering.

  16. Louis Fyne

    Generally non-rich people in Italy, do not eat a stereotypical “Mediterranean” diet on their sunlit Tuscan patio— it’s processed/industrialized. And it’s more processed as you go down the income scale.

    And most processed foods have some form of vegetable oil, soybean, corn, canola, etc. Cooking vegetable oil at high temps produce chemicals that have possible links to increased heart disease and cancer. And not to mention this study is from the days of trans fats from hydrogenated oils. All bad for health outcomes.

    not to mention that even “the perfect diet” won’t protect you from the negative by-products of poverty-related stress: finding a job, paying bills, long commutes, self-medicating via booze or sugar, etc.

    Bottom line: try to avoid eating stuff that’s from an assembly line.

  17. reslez

    “meaning even though the Mediterranean diet may not have led to better results, they would have been worse off had they not followed it.”

    Ok, but the study showed the opposite, so speculating along those lines confuses the issue. The study found no evidence that not following the diet led to worse outcomes — it showed that it had no effect.

    It makes me wonder if some of the early studies tracked people who still followed traditional lifestyles, meaning low social inequality and a more relaxed pace of life. If low status leads to more stress, a more traditional lifestyle with family ties and smaller communities could have a protective effect, as was presumably the case in some of the island Mediterranean populations that were originally studied and led to all the hype about the Mediterranean diet.

    Subsequent studies that showed a protective effect to the diet itself may have had small sample sizes and other issues. The reproducibility crisis in nutrition and medical related research is extremely important and should be considered every time one comes across diet and nutrition news these days. In this case, such a large number of people were tracked that this study has a bit more credibility than the usual ones. Meta-analysis and “studies of studies” where very small samples are statistically merged together, and where the underlying studies may have used P-hacking and all manner of dubious techniques, are a bit shadier to my mind.

    1. Yves Smith Post author

      Read the whole sentence. You took ONE PART of a complex sentence and used it to misrepresent what I said. The sentence is of the “One has to wonder whether X, then Y” form. That is equivalent to “If X, then Y”. You eliminated the “if X” part. If you can’t comprehend writing at a post graduate level (which is where this site scores) you should not be commenting here.

  18. PlutoniumKun

    Just as a counterargument to the issue of health and inequality here, there was an interesting article on Korea in the Guardian – it suggests that in Korea relatively long life expectancy goes hand in hand with a high level of inequality.

    It does speculate that it may be a generational thing – people in old age now lived much healthier lives with a better diet, etc. Also worth noting that Korea has a pretty good health system.

  19. Ned

    Perhaps higher educated people have more of an *expectation* that their lifestyle and diet choices, with an emphasis on choices, can control their fate and therefore there’s some placebo effect on stress?

    Also, did they factor in the inherent and storage vessel toxins in cheap liquor and beer and wine, plus overall alcohol consumption, versus say finer brands/quality that would differ between classes and income levels?

  20. Tooearly

    The problem with studies like this is that they seem to assume that eating is exclusively about nutrition. It s not. Eating should be about connections: to the land, to your family, to your sense of self, to your ancestors. Perhaps the recommended diet doesn’t satisfy those forms of hunger equally to all groups.

    1. vidimi

      that’s a very good point. healthy eating is also taking the time to eat slowly. poorer people are probably more likely to eat rushed. this is bad for the digestive tract.

  21. Victoria

    Without having read the study I am fairly certain that it reflects the fact that diet is only one factor in overall health, and not nearly as important as I would have expected it to be. Smoking, drinking, working long hours, and stress factors are also important, and may be significant enough to drown out the benefits of a healthy diet.

  22. Edward

    What about childhood? Did the study ask what kind of diet the subjects had growing up? Maybe the school lunches for the poor are less healthy then for the rich/educated, and hurt them later in life.

    1. Edward

      Someone once told me that he once observed a box of hot dogs in his school cafeteria that were labeled “grade D but edible”.

      Did the study take into account the use of drugs such as antidepressants?

  23. Paulcito

    Loneliness kills, love heals. Healthier food and exercise make a difference but they aren’t the answer to the mystery of life. Live long enough and the body will fail and physical health will collapse. Even Jack LaLanne had to die.

    But what about the soul? The meaning of life? Magic and mystery and that strangely beautiful elevating feeling, like you feel when you put on that David Bowie CD? Maybe there is an answer that transcends the physical stuff and health habits. Bowie was never a foodie or health nut by any means but you know, he loved and did his thing and it was real and seemed totally at peace when he left us. What else truly better could anybody do here?

  24. witters

    Why this obsession with all things dietary? It is like my television. It has the same obsession.

    1. Yves Smith Post author

      Many people with adequate to high incomes are worried about food safety. And most people in America are fat and would like to be less fat but haven’t found a way to get and stay thin.

      In addition, since heart disease exploded in the US after WWII, the medical profession has acted as if it is largely about diet without any solid research as to how and why that might be the case, so they’ve been flailing around with diet recommendations.

  25. Wade Riddick

    Were the lower cohorts drinking soda?

    Here are the other factors to consider:

    The poor live in more polluted areas and are more exposed to communicable disease. Have you ever actually seen the living situation of many poor people? The air is often toxic both indoors and out. This leads to more infections, resulting in more antibiotic exposure. Killing friendly gut flora triggers more obesity and inflammation. This is, by the way, inherited from the mother during birth. Fiber intake may not matter much if you’re not feeding any friendly bacteria with it. Poor neighborhoods are also less likely to have safe outdoor spaces for sun exposure and play/exercise.

    The poor are subject to greater daily stress through discrimination and financial predation. Their job situation is more precarious and their bosses less sympathetic. Chronic stress leads to more inflammation and insulin resistance. Higher social status has a protective benefit. Limited vocabulary and educational opportunities contributes to this. Ignorance makes it harder to cope with stress, especially if you’re encountering hostile police on a regular basis or gangs.

    It’s hardly the olive oil alone. The foods sold to poor people may look “healthy” but, in fact, are still filled with sugar. Even Morton salt has sugar (“dextrose”) in it. If you’re ordering this “Mediterranean” diet in restaurants, you are totally screwed. They’re probably using canned sauces and other hyperprocessed ingredients.

    Decaying infrastructure. The poor are more likely to drink water from lead pipes or live near noisy overpasses or airports.

    Being poor and eating a fancy Mediterranean diet may itself cause stress. Other poor people take it as a personal insult when others from the neighborhood buy different shoes or cars – and certainly when guests don’t eat the food offered (even if it’s junk). Their money is dear and they want social confirmation that they made a good purchasing decision. There are neighborhood norms for clothes, cars, shoes and – I would imagine – even food, especially at social events like block parties and ball games. You may be sending a political signal that makes you the active target of hate. Wealthier cohorts are just the opposite and demand diversity in fashion and other purchases to demonstrate a distinct personal style.

    Health care. Only the very wealthy are likely to have enough funds on hand to deal properly with a health emergency.

    Family. It’s hard to afford marriage and kids these days, resulting in many more people who are totally on their own.

    Epigenetics. Adverse methylation and other genetic modifications are passed down to children from parents. Trying to overcome them is like running up a hill. Even if you fix all of the above for an individual, whatever happened to their parents will still come down on them like a ton of bricks.

    1. Lambert Strether

      > Epigenetics. Adverse methylation

      What is adverse methylation? (To epigenetics I would also add lead, and I would bet the poor are also concentrated near freeways, so all that comes from that.)

      1. Wade Riddick

        It’s the addition of a methyl group to a gene, muffling its expression. Methylate the glucocorticoid receptor (GR), for instance, and you get Crohn’s disease because the body is insensitive to the actions of glucocorticoids and can’t shut down inflammation in the gut. GR isn’t made, doesn’t migrate to the cell surface, can’t bind with cortisol and can’t activate GR transcription.

        Stress and pollution do all kinds of damage through methylation and other epigenetic marks (there are more than 100+ types). Last time I looked at lead poisoning, methylation took a big hit.

        Methylation marks are inheritable and can be altered with heavy amounts of, say, B vitamin consumption. Fiber production in the gut affects the epigenetic process of histone acetylation (fiber/probiotics -> butyrate ( + carnitine/OTCN2) -> PPARalpha -> beta-oxidation -> HDAC inhibition -> affects, regulatory T-cells, mu opioid receptor expression and hundreds of other system which affect inflammation, cancer development, neurogenesis, AMPK (metabolism), antiviral defense, etc, etc.).

  26. JohnM

    Anyone interested in this topic should read Nina Teicholz book ‘the big fat surprise’. notwithstanding the title that makes it sound like some sort of fad diet book, it’s a serious investigation into the nutritional studies, including the infamous ‘seven counties study’, that became the basis for both the ‘mediterranean diet’ and our global fat phobia.

    and if that book makes you think twice about the scientific validity of our national dietary advice, then also read ‘good calories, bad calories’ by gary taubes.

  27. vidimi

    to me, you can’t have a mediterranean diet without drinking lots of wine.

    the wealthier folks probably consumed lots of anti-oxidant-high nebbiolo whereas the poor probably just drank supermarket plonk/antifreeze.

  28. peter brown

    most research is not reproducible , and I would imagine research in the nutritional field is even worse.

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