Font Size

- Aa +

Tue 23 Sep 2008 04:00 AM

Font Size

- Aa +

Translating good food into better diets

Four diets forged in clinical trials offer real benefits for the entire cardiovascular system.

Four diets forged in clinical trials offer real benefits for the entire cardiovascular system.

Do the basics of healthy eating - more fruits, vegetables, good fats, whole grains, and healthful protein packages, and less of the not-so-good stuff - work for the heart? Indeed they do.

A host of studies has shown that each of these elements, by itself, can lower cholesterol, blood pressure and blood sugar; improve the flexibility of arteries; or protect against heart attack, stroke, and other forms of cardiovascular disease. Put various pieces together and the protective effect is even more powerful.

There are scores of 'healthy heart' diet books in the marketplace. Very few of those diets, though, have been tested to see how well - or even if - they work.

If you are a do-it-yourself-er, don't hesitate to wade right in and fiddle with your diet. After all, this isn't rocket science, and only you know what foods you like, which ones you can't stomach, and what kinds of dietary changes you can realistically make.

But what if you'd rather have someone else cook up a diet to help you counter or prevent heart disease? There are scores of "healthy heart" diet books in the marketplace. Very few of those diets, though, have been tested to see how well - or even if - they work.

Four diets forged in rigorous clinical trials are the real McCoy. These are the DASH diet, a higher-protein diet, the cholesterol-lowering portfolio diet, and a Mediterranean-type diet.

These four are much better for the heart than the average American diet. Yet each has its own subtle effects that, in some cases, could detract from the benefits, and none except the Mediterranean-type diet has been studied long enough to know exactly how it affects heart disease or survival.

Here's how four rigorously tested diets stack up in composition and in how they affect six key aspects of cardiac riskDASH:Seven to nine servings a day of fruits and vegetables; two to three servings of low-fat dairy products; emphasis on whole grains, nuts, poultry, and fish; minimal saturated fat, red meat, and sweets (55% of calories from carbohydrates, 18% from protein, and 27% from fats).

OmniHeart higher protein:Six servings a day of fish, poultry, red meat, and eggs; three servings of beans, nuts, seeds, or soy; plenty of fruits and vegetables; and some low-fat dairy products (48% of calories from carbohydrates, 25% from protein, and 27% from fats).

Portfolio diet:Five to 10 servings of fruits and vegetables; whole grains instead of highly refined ones; mostly plant protein; soy foods instead of meat, soy milk instead of dairy; plenty of soluble fibre from oats, barley, eggplant, okra, and natural psyllium supplements; margarine enriched with plant stanols or sterols, such as Benecol or Take Control; nuts, preferably almonds, every day (48% of calories from carbohydrates, 21% from protein, and 31% from fats).

Mediterranean-type diet:There is no such thing as the Mediterranean diet. In general, a Mediterranean-type diet is low in saturated fat and high in fibre; fruits, vegetables, grains, beans, nuts, and seeds are eaten daily and make up about half of the diet; fat, much of it from olive oil, may account for up to 40% of daily calories; cheese or yogurt usually eaten each day, along with a serving of fish, poultry, or eggs; red meat on occasion.

You can assume that the improvements that all four yield in cholesterol levels and blood pressure will translate into protection against heart attack or stroke. But when it comes to nutrition, making assumptions can be tricky.

Four for the heart

Here is a sketch of this quartet of carefully tested diets and how they stack up against heart disease.

These four diets are alike in many ways. They are heavy on food from plants (fruits,vegetables, beans, nuts, and seeds) and light on saturated fat, sodium, and sweets.

A dose of DASH. The Dietary Approaches to Stop Hypertension trial tested a diet that emphasised fruits, vegetables, and low-fat dairy foods and limited red meat, saturated fats, and sweets.

Compared with an average American diet, the DASH diet lowered systolic blood pressure (the upper number of a blood pressure reading) by 5.5 points and diastolic pressure (the lower number) by 3 points.

A low-sodium DASH diet worked even better. The DASH diet lowers levels of harmful LDL (bad) cholesterol and triglycerides, the main fat-carrying particles in the bloodstream. On the downside, it also reduces protective HDL ("good") cholesterol.

Help from protein. One of the diets tested in the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart, for short) replaced some carbohydrates of the DASH diet with additional good protein. This strategy lowered LDL and triglycerides and dropped blood pressure a bit more than the original DASH diet. But it, too, harmed HDL.

Improve your portfolio. Researchers at the University of Toronto created what they called a "dietary portfolio of cholesterol-lowering foods." It went after cholesterol by adding specific foods known to lower cholesterol: margarine enriched with plant sterols; oats, barley, psyllium, okra, and eggplant, all rich in soluble fibre; soy protein; and whole almonds. It substantially lowered LDL, triglycerides, and blood pressure, and did not harm HDL.

Mediterranean-type diet. The basics include fruits, vegetables, grains, beans, and nuts supplemented with some cheese or yogurt, fish, poultry, and eggs. It's beneficial across the board for cholesterol, blood pressure, and other cardiovascular risk factors.

In one long-term study, heart attack survivors who followed a Mediterranean-type diet suffered far fewer heart attacks, strokes, or other cardiovascular problems than survivors following a standard low-fat diet.

Bringing it home

These four diets are alike in many ways. They are heavy on food from plants (fruits, vegetables, beans, nuts, and seeds) and light on saturated fat, sodium, and sweets.

Pay now or pay (more) later

If it seems like it costs a lot to eat a healthful diet, consider what it costs if you don't. Northwestern University researchers tallied up hospital-related charges for more than 1,000 middle-age men who signed up to be in a long-term study in 1958 and 1959.

Between 1984 and 2000, Medicare paid an average of $133,000 per man for those who reported getting zero to two servings of fruits and vegetables a day and $93,000 for those getting three or more.

This doesn't include costs for prescription drugs, out-of-pocket payments, nursing home care, or other expenses, nor does it include the added health benefits (and thus savings) from switching to healthier fats, carbs, and protein packages.

They aren't vegetarian, although the portfolio diet comes pretty close. Instead, they are "flexitarian" - they emphasise healthy plant foods, but also include poultry, seafood, dairy foods, and sometimes even steak.

The DASH and Mediterranean-type diets have been translated into popular books with meal plans and recipes. The OmniHeart and Portfolio approaches haven't.

From reports in medical journals, we've put together some daily meal plans that can give you ideas for setting up your own version.

Notice that the standard low-fat diet - less than 20% of calories from fat - isn't on the list. It was designed as a way to get people to eat less saturated fat, which is a good thing. But it also enticed dieters to see all fat as a villain.

That isn't so good, since unsaturated fats are actually good for the heart.

What's more, cutting back on fat often meant that people ate more refined starches and sugar, a dietary move that does the heart no favours. In clinical trials, the DASH, OmniHeart, and Mediterranean-​type diets both soundly trumped a low-fat approach.

That's not to say the low-fat approach is bad. It works for some people. Dr. Dean Ornish uses it as one part of an effective program that also includes exercise and stress management.

The trick is adding healthy, slowly digested carbohydrates and sticking with the diet. Low-fat diets are generally harder to follow for long periods than a Mediterranean-type diet, which is more varied.

Celebrating differences

The most encouraging finding from trials comparing weight-loss diets is that long-term weight loss can be accomplished by a variety of ways - there's no one-size-fits-all strategy. The same will probably hold true for heart healthy diets. What's important is to find a plan you can stick with for a long lifetime.

Source: Harvard Health Publications. Copyright © 2008 President and Fellows of Harvard College. All rights reserved.

More information

The DASH diet:"Your Guide to Lowering Your Blood Pressure with DASH" is a 64-page booklet from the National Heart, Lung, and Blood Institute. It costs $3.50 if ordered by phone (301-592-8573) or can be downloaded for free at health.harvard.sdu/122.

Two independent books, The DASH Diet Action Plan by Marla Heller and The DASH Diet for Hypertension by Thomas Moore and Mark Jenkins, are also available from most book sellers.

OmniHeart and portfolio diets:To see summaries of these diets along with sample meal plans, visit health health.harvard.sdu/123. If you don't have access to the Internet, send a note asking for this diet summary to Diet Plans, c/o Harvard Heart Letter, 10 Shattuck St., 2nd floor, Boston, MA 02115.

Mediterranean diet:Ever since nutrition researcher Ancel Keys and his wife, Margaret, published How to Eat Well and Stay Well the Mediterranean Way in 1959, more than a dozen books describing the Mediterranean diet, most with recipes, have been published. One of the newest is Your Heart Needs the Mediterranean Diet by Emilia Klapp, a registered dietitian.

For all the latest health tips & news from the UAE and Gulf countries, follow us on Twitter and Linkedin, like us on Facebook and subscribe to our YouTube page, which is updated daily.