Currently browsing posts about: Mediterranean diet

Christopher Gardner writes me that the next time I need an example of an industry-funded study, I should take a look at this one.  Happy to.

The Study: A Mediterranean-Style Diet with Lean Beef Lowers Blood Pressure and Improves Vascular Function: Secondary Outcomes from a Randomized Crossover Trial.  Jennifer A Fleming, Kristina S Petersen, kup63@psu.edu, Penny M Kris-Etherton, David J Baer. Current Developments in Nutrition, Volume 9, Issue 4, 104573.

Objectives: “The aim was to evaluate the effects of a MED diet incorporating 0.5 oz./d (MED0.5), 2.5 oz./d (MED2.5) and 5.5 oz./d (MED5.5) of lean beef compared with an Average American diet (AAD) on vascular health [brachial and central blood pressure, pulse wave velocity (PWV), and augmentation index].”

Methods: “In random sequence order, participants consumed each test diet for 4 wk. Vascular outcomes were assessed at baseline and the end of each diet period.”

Results:  “PWV was lower following MED0.5…and MED2.5… compared with the AAD; PWV was nominally lower after the MED5.5 compared with the AAD…Central systolic blood pressure was lower following the MED0.5…and MED2.5…compared with the AAD…Brachial systolic and diastolic pressure were lower following all 3 MED diets compared with the AAD (P < 0.05).

Conclusions: Compared with an AAD, MED diets containing 0.5 and 2.5 oz./d of lean beef improved brachial and central systolic and diastolic blood pressure and arterial stiffness. Our findings suggest that a MED diet with ≤5.5 oz./d of lean beef does not adversely affect vascular function.

Conflict of interest: JAF received travel funds from the National Cattlemen’s Beef Association for giving presentations on this research. PMK-E and DJB received funding from the National Cattlemen’s Beef Association for the research reported in this article. KSP has received grants from the National Cattlemen’s Beef Association to conduct other research projects. KSP has also received honoraria from the National Cattlemen’s Beef Association for consulting work unrelated to the research presented in this paper.

Comment:  Professor Gardner noted that the AAD diet contained 3,500 mg sodium/day, whereas all three of the Mediterranean/beef diets had lower sodium (<2,300 mg/day).  Could reduced sodium have anything to do with the reduced blood pressure observed on the two diets containing lower amounts of beef (Med 0.5 and Med 2.5)?  The authors, alas do not discuss this point.  This makes this study appear to have been designed to demonstrate that eating beef does not adversely affect blood pressure.  Research on the effects of industry funding demonstrate that funders do not need to have a role in the design, conduct, etc of a study to exert influence.  Consciously or unconsciously, intentionally or unintentionally, funding recipients want to please their sponsors.  Studies of the effect of diet on blood pressure need to control for sodium intake.

I learned about this from reading a headline in FoodNavigator-Asia: Mediterranean diet linked to reduced neurodegeneration in elderly Chinese.

This got my attention: Why would anyone be studying the Mediterranean diet in Chinese people.  The traditional Chinese diet, like that of the Mediterranean diet, is largely plant-based and strongly associated with health and longevity.

But here we have it.  Basically, they want to know if this diet works in Chinese as well as North American and Oceanic populations.  As so it does.

The study: Association of adherence to the Chinese version of the MIND diet with reduced cognitive decline in older Chinese individuals: Analysis of the Chinese Longitudinal Healthy Longevity Survey.  The Journal of nutrition, health and aging.  Available online 1 January 2024, 100024

• Purpose: This study aimed to assess the correlation between the Chinese version of the MIND (cMIND) diet and cognitive impairment in older Chinese individuals.  [MIND = Mediterranean-Dietary Approaches to Stop Hypertension (DASH) diet intervention for Neurodegenerative Delay].
• Method: The cMIND diet score (cMINDDS) was calculated by assessing dietary patterns based on survey responses.
• Results: The increased cMINDDS was associated with a reduced risk of cognitive impairment. Higher consumption of fresh fruits and nuts was associated with a decreased risk of cognitive impairment (OR = 0.77, 95% CI: [0.66, 0.89] and OR = 0.70, 95% CI [0.58, 0.86], respectively).
• Conclusion: Adherence to the cMIND diet was associated with lower risks of cognitive impairment in older Chinese individuals.

About the diets

The MIND diet recommended 10 brain-healthy food groups (green leafy vegetables, other vegetables, nuts, berries, soybeans, whole grains, not fried fish, not fried poultry, olive oil, and wine) while avoiding five unhealthy groups (red meat and products, butter/margarine, cheese, pastries and sweets, and fast fried foods).

The cMIND diet comprises 12 components: staple food composition, quantity, fresh vegetables, mushrooms or algae, fresh fruits, fish, cooking oil, soybeans, nuts, garlic, tea, and sugar.

Here’s a quick comparison:

Comment:  Both diets are healthy.

Bottom line (can’t be emphasized enough, apparently): Eating a healthy diet is good for health.

Thanks to a reader in Israel, Yehuda Ben-Hur, for sending this one.

The study: The effect of a high-polyphenol Mediterranean diet (Green-MED) combined with physical activity on age-related brain atrophy: the Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed Study (DIRECT PLUS) .  Alon Kaplan, Hila Zelicha, Anat Yaskolka Meir, Ehud Rinott, Gal Tsaban, Gidon Levakov, Ofer Prager, Moti Salti, Yoram Yovell, Jonathan Ofer, Sebastian Huhn, Frauke Beyer, Veronica Witte, Arno Villringer, Nachshon Meiran, Tamar B Emesh, Peter Kovacs, Martin von Bergen, Uta Ceglarek, Matthias Blüher, Michael Stumvoll, Frank B Hu, Meir J Stampfer, Alon Friedman, Ilan Shelef, Galia Avidan, Iris Shai.  The American Journal of Clinical Nutrition, nqac001, https://doi.org/10.1093/ajcn/nqac001 Published: 11 January 2022.

Objectives: We aimed to explore the effect of a Mediterranean diet (MED) higher in polyphenols and lower in red/processed meat (Green-MED diet) on age-related brain atrophy.

Methods:  Abdominally obese  participants were randomly assigned to follow one of three diets: (1) healthy dietary guidelines (HDG), (2) MED, or (3) Green-MED diet.  The two MED groups consumed 28 g walnuts/d.  The Green-MED group consumed green tea , mankai (100 g frozen cubes/d as a green shake).  After 18 months, participants got MRI scans.

Results: Indicators of brain atrophy were attenuated in both MED groups, with the best outcomes among Green-MED diet participants.  Therefore, greater Mankai, green tea, and walnut intake and less red and processed meat were significantly and independently associated with reduced atrophy decline .

Conclusions: A Green-MED (high-polyphenol) diet, rich in Mankai, green tea, and walnuts and low in red/processed meat, is potentially neuroprotective for age-related brain atrophy.

Funding: Supported by German Research Foundation, Israel Ministry of Health, Israel Ministry of Science and Technology, and the California Walnut Commission (to I Shai, the senior author). “None of the funding providers were involved in any stage of the design, conduct, or analysis of the study, and they had no access to the study results before publication.”

Comment: I hardly know what to make of this study, which involves so many variables: mankai, (duckweed, supposedly a polyphenol-rich “supergreen”), green tea, walnuts, and low red/processed meat.  The MED groups were instructed to consume a calorie-restricted Mediterranean diet “rich in vegetables, with poultry and fish partly replacing beef and lamb.”  Physical activity instructions (and gym memberships) as well nutrition counseling was also part of this mix.

My questions:

• Why not test the Mediterranean diet on its own without all those polyphenol additives?
• Why walnuts as opposed to any other polyphenol-containing food?  Could sponsorship have anything to do with this choice?
• Why Mankai, which is traditionally a component of Asian diets, not Mediterranean?    Why are Israeli scientists so interested in this plant?
• Don’t classic Mediterranean diets provide enough polyphenols to be protective against brain atrophy?

I will be intersted to see further studies along these lines.