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Diets And Heart Health: Which One Offers The Best Protection?

M3 India Newsdesk May 20, 2023

A recent BMJ analysis compared seven popular structured diets on mortality and cardiovascular disease (CVD) events in at-risk adults. It is crucial for practitioners as it identifies the diets that reduce the risk of death and nonfatal heart attacks in high-risk patients.

Key messages

  1. A review of diet studies revealed that a low-fat diet and the Mediterranean diet were the two that had the most positive effects on cardiovascular health.
  2. Fish, fruits, vegetables, and monounsaturated fats like olive oil are prioritised in the Mediterranean diet.
  3. The Mediterranean diet, low-fat diets, very-low-fat diets, modified-fat diets, combined low-fat and low-sodium diets, and the Ornish and Pritikin diets were the seven diets that the researchers evaluated.
  4. A low-fat diet that also lowered sodium consumption did not perform as well as a low-fat diet that did not cut salt intake, perhaps highlighting the challenges of performing randomised, controlled studies like the ones being considered.

The Mediterranean diet or a low-fat diet are the best choices for adults at risk of cardiovascular disease, according to a recent analysis of randomised, controlled studies published in BMJ.

Benefits to health were compared between seven different diets and no diet at all in this comprehensive review and meta-analysis of the literature. These diets included the Mediterranean diet, low-fat diets, very-low-fat diets, modified fat diets, combined low-fat and low-sodium diets, the Ornish diet, and the Pritikin diet.

According to the analysis, a Mediterranean diet lowers the risk of cardiovascular disease, stroke, and non-fatal heart attacks.

All-cause mortality, non-fatal heart attacks, and unforeseen cardiovascular treatments were all decreased by low-fat diets. Although a low-fat and low-sodium (salt) diet may be helpful for patients at high risk of stroke, the other diets did not provide any conclusive evidence of improving cardiovascular health.

35,548 individuals in the 40 studies that made up the review were monitored for an average of three years after the commencement of the trials. The review's main emphasis was on adults who had cardiovascular disease or two or more cardiovascular risk factors.

Why this study is important?

For people with elevated CVD risk, dietary recommendations promote a variety of diets coupled with physical exercise or other cointerventions, but they often rely on information with a poor degree of credibility from nonrandomised trials and surrogate outcomes.

The benefits of some dietary programmes have been reported in several meta-analyses of randomised controlled trials with mortality and significant CV outcomes; however, the authors note that those studies did not use network meta-analysis to provide absolute estimates and certainty of estimates for adults at intermediate and high risk.

In order to examine the effects of seven well-known structured diets on mortality and CVD events for persons with CVD or CVD risk factors, Karam and colleagues did a thorough systematic review and network meta-analysis.

Choosing between a Mediterranean and low-fat diet

Vegetables and fruits are prioritised in the Mediterranean diet as well as many other low-fat eating plans. The consumption of fish and monounsaturated fats is also increased by the Mediterranean diet.

Experts claim that the Mediterranean diet is more beneficial because it places a little more emphasis on lean protein and the use of olive oil and other vegetable oils in lieu of animal fats while cooking.

The quality of the diet that the individual is following actually determines if one diet is healthier than another. Instead of focusing on specific nutrients like saturated vs unsaturated fats, it's critical to consider the overall nutritional quality of a meal. There is no strategy that works for everyone.

Heart-health benefits of certain oils

The use of olive oil was linked in this research—likely the biggest investigation of the Mediterranean diet to date—to a considerably lower risk of cardiovascular events.

Olive oil, avocado oil, and flax seed oil put on top of cooked dishes were all highly suggested by experts.

Although these ingredients can be pricey, it is also claimed that using cheaper vegetable oils, such as soybean, canola, corn, and sunflower oil, is "much better certainly than using butter, shortening, margarine, other types of synthetic oil, and things like that" in terms of cardiovascular health.

Reduced salt intake with a low-fat diet falls short

The study's conclusion that low-fat diets fared less well when paired with a decrease in salt may come as a surprise to some people. Despite their overall good performance, low-fat diets did well overall.

Two scenarios might account for this. According to a 2018 Lancet research, lowering salt intake may not be as advantageous as some people believe.

Researchers discovered in that study that salt consumption over five grammes per day only enhanced cardiovascular risk. The U.S. National Institutes of Health recommend that those with high blood pressure consume no more than 1.5 grammes of salt per day. Increased potassium was shown to reduce the risk of cardiovascular disease by the same research. This demonstrates the need of considering dietary changes holistically rather than, in this instance, concentrating on single nutrient modifications (or two nutrients).

The research's shortcomings

When taking part in a study, participants' burden may be appreciated, as can the challenges researchers have in persuading them to commit to the procedure for lengthy periods of time. The inability to assess adherence to diet plans is one of the study's limitations, and it's possible that some of the advantages came from other sources, such as pharmacological therapy and assistance with quitting smoking.

The investigations did not provide enough information to determine how the diets affected peripheral vascular events, atrial fibrillation, angina, and heart failure.


Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Monish Raut is a practising super specialist from New Delhi.

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