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Published in Cardiology and
Journal Scan / Research · April 19, 2023

Comparison of Seven Popular Structured Dietary Programmes and the Risk of Mortality and Major Cardiovascular Events in Patients at Increased Cardiovascular Risk
BMJ : British Medical Journal
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This large meta-analysis examined randomised controlled trials to assess the effects of seven popular diets (low-fat; Mediterranean; very low–fat; modified fat diet with a higher proportion of polyunsaturated fats; combined low-fat and low-sodium; Ornish; and Pritikin) on mortality. The results showed mortality benefits with the Mediterranean and low-fat diets only, with the Mediterranean diet having the additional benefit of being protective against stroke (low-fat diets also protected against all-cause mortality).

These results show further evidence of the benefits of the Mediterranean diet in mortality, stroke, and cardiovascular disease prevention. Low-fat diets had fewer benefits, whereas the popular Ornish and Pritikin diets had no observable benefits.
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Dietary influence on inflammation and insulin resistance

This network meta-analysis looked at several popular diets and found that the Mediterranean diet had the greatest effect on all-cause mortality, nonfatal myocardial infarction, and stroke in patients with high cardiovascular risk. The low-fat diet also showed benefits for all the above, except stroke.

A plant-forward Mediterranean diet and a low-fat diet reduced inflammation and insulin resistance, two dietary effects, which a study involving 205,852 healthcare professionals followed for 32 years found to have the greatest effect in reducing heart disease, diabetes, and cancer.1

Those patients who had the highest MED score (below) compared with those who had the lowest MED score had a 28% reduced risk of having a primary cardiac event.2

MED score (one point for each, 1–9)

Vegetables (not including potatoes)
Fruit
Nuts
Whole grains
Legumes
Fish
Monounsaturated fat (olive oil)
Little or no red and processed meat
One beer or 4-oz glass of wine daily
Number 9 (EToH) is controversial. If there is a high risk of cancer, alcohol should be avoided altogether.

A recent story of the week reviewed a paper suggesting that inflammation was a significant unaddressed risk factor in patients on statins. Being on a statin is not enough. We need to also address inflammation.

Shah and colleagues3 quantified those underlying pathophysiologic processes that have the most effect on increasing the risk of a cardiovascular event. They also concluded that inflammation and insulin resistance were at the top.

Most powerful factors affecting CV risk

Inflammation, 29.2%
Insulin resistance, 27.9%
Body mass index, 27.3%
Blood pressure, 26.6%
Lipids, 26%
Both the Mediterranean diet and the low-fat diet reduce inflammation by reducing fat intake. Saturated fat is high in arachidonic acid, which fuels the inflammatory cascade. The Mediterranean diet is high in fiber, which slows the absorption of sugar (glycemic index) and protects against insulin resistance.

A growing nutrition concern that has not been in the literature long enough for a network meta-analysis to evaluate is that of non-nutritive sweeteners. These have been associated with increasing platelet aggregation and insulin resistance.4,5

Health is much more about what we do than what we take. Nutrition and exercise continue to be the most effective, evidence-based interventions in preventing the number one cause of death on the planet. Maybe we should invest more in supporting these interventions in our communities, thereby reducing the need, cost, and risk of polypharmacy.

G Mohan