Searching for a Heart Healthy Diet-Mayo Clinic Proceedings

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http://www.mayo.edu/proceedings/2003/nov/7811e1.pdf

 

Diabetes and Heart disease have continued to progressively increase

during the past decade with a marked decrease in physical activity

and exercise as well as an increase in caloric intake in the western

world. The realization has resulted in a wide spectrum of diets

designed to decrease cardiovascular disease and to decrease weight.

 

The philosophies behind these diets are as far reaching as the

swing of a pendulum, with the extremes of swing representing

the `fringe diets'. At one extreme is the very low fat Dean Ornish

diet, with the other extreme, the contralateral swing, being the

high-fat and carbohydrate restricted Atkins diet. Clearly, both the

Ornish and the Atkins diets lead to weight loss without caloric

restriction, whereas all the other more `common-sense' diets require

caloric restriction to achieve weight loss.

 

Many well-documented studies have confirmed that long-term

adherence to extremely low-fat diets decreases cardiovascular

events, produces weight loss, and improves lipid profiles.Weight

loss was more substantial in the Atkins group at 3 months but not

significant at 12 months. The absolute difference in weight was only

4%. Triglyceride and HDL levels increased, however total

cholesterol and LDL cholesterol levels also increased.

 

One study examined morbidly obese patients. All patients had

atherosclerotic heart disease.

A high saturated fat and starch avoidance diet was used with one

half the calories from saturated fat, red meat, cheese, and low fat

protein. Fasting glucose, fasting insulin, and TG levels decreased.

Total cholesterol and HDL cholesterol did not show any specific

change.

However, cholesterol particle size and LDL size increased

significantly!

 

Of note, plasma homocysteine concentrations and C-reactive protein

increased in the duration study.

The one long term study comparing the Atkins diet with various other

diets for one year showed that on the Atkins diet, homocysteine

concentrations, C-reactive protein and lipoprotein(a) all increased!

 

This study showed that with a high fat diet, LDL cholesterol and

total cholesterol levels increased, HDL levels decreased, and the

cholesterol to HDL ratio became abnormal, all suggesting that the

diet may have important long-term limitations.

Long term adherence to fringe diets is often limited because these

diets may be tolerated poorly.

 

A profusion of data has been published regarding the Mediterranean

diet and the American Heart Association diet with the use of n-3

fatty acids which require caloric restriction.

These diets, particularly the Mediterranean diet, offer far more in

terms of protection from coronary artery disease and intuitively

make more sense.

 

I am concerned about the long term cardiovascular risks of the

Atkins diet shown in the published studies.

I recommend that we continue to study its metabolic effects.

 

We should continue to examine the risk-benefit profiles of caloric-

restricted, more rational diets such as the Mediterranean diet,

which recently was associated with a striking decrease in

cardiovascular risk, as noted in the study from Greece that followed

up adherence to this diet.

 

Gerald T. Gau, MD

Division of Cardiovascular Diseases

Mayo Clinic

Rochester, Minn