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[NUTRITION ADVISER]

Fruits and Veggies: Are You Getting Enough of a Good Thing?

Susan M. Kleiner, PhD, RD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 11 - NOVEMBER 96


You've probably been hearing it since grade school: Eat your fruits and vegetables and you'll be healthy. Sometime between then and now, you may have grown skeptical of that advice. It seems too simplistic. Human health and nutrition science must be more complicated than that, right?

Well, after wading through reams of research reports, nutritionists have found that the science is, indeed, complicated. But they've also found that the advice is still worth giving.

Fruit and Veggie Benefits

The reasons to eat lots of fruits and vegetables are many. Not only do plant foods help lower dietary fat and control body weight, they can also help fight disease.

At first, nutritionists touted fruits and vegetables because they are packed with vitamins and minerals. Now we recommend eating plenty of plant foods to ensure a diet rich in vitamins, minerals, fiber, and other substances that might fight cancer, like antioxidants (beta-carotene and vitamins A and C). Taking a vitamin-mineral supplement or other supplement cannot match the benefits gained from eating food (see "Powerhouse Produce," below).

Powerhouse Produce

Nutritionally speaking, fruits and vegetables are not all created equal. Which plants pack the biggest nutritional punch?

Heaviest hitters from the fruit bin are:
  • Oranges
  • Strawberries
  • Kiwi
  • Cantaloupe
  • Peaches and nectarines
  • Grapes
Best bets from the veggie section are:
  • Broccoli
  • Spinach
  • Peppers (especially red)
  • Sweet potatoes
  • Onions
  • Tomatoes

Recent research gives plenty of ammunition to the pro-plant-food faction. For example, two studies (1,2) found that fruits and vegetables can help reduce the risk of stroke. Other studies reveal that:

  1. eating vegetables decreases the risk of liver cancer (3),
  2. eating onions lowers the rate of stomach cancer (4), and
  3. eating a lot of foods rich in the substance lycopene—primarily found in tomatoes and tomato products—lowers the risk of prostate cancer (5).

These and other study results have led to revisions in dietary recommendations.

The Power of the Pyramid

The traditional strategy of eating foods from four equally important food groups—milk, meat, fruits and vegetables, and grains—was widely used. In 1992, though, after research had clearly demonstrated that the four food groups were not nutritionally equal, the federal government developed the Food Guide Pyramid (6). The pyramid shows that plant foods—grains, vegetables, and fruits—need to be the foundation of our diet. Smaller quantities of dairy, high-protein foods, fats, oils, and sweets should be eaten.

Table 1. Fruit and Vegetables: What Counts as a Serving?
Fruit
1 medium piece of fruit like apple, banana, or orange
1/2 cup of chopped, cooked, or canned fruit
3/4 cup of fruit juice

Vegetables
1 cup of raw leafy vegetables
1/2 cup of other vegetables—cooked or chopped raw
3/4 cup of vegetable juice
Adapted from the US Department of Agriculture (6).

The Food Guide Pyramid now has more specific guidelines that separate vegetables from fruits and recommend more daily servings of each. According to the pyramid, a diet that contains 1,600 calories per day should contain at least three servings of vegetables and two servings of fruit. A diet of 2,800 calories per day should have at least five servings of vegetables and four servings of fruit. Table 1 helps clarify what constitutes a serving.

The Food Guide Pyramid de-emphasizes animal foods because the body does not require a large serving to get the nutrients found in these foods and because they tend to be high in fat and saturated fat.

Changing Dietary Guidelines

The federal government's Dietary Guidelines for Americans complement the Food Guide Pyramid. The original Dietary Guidelines, which were developed by the US Department of Agriculture in the early 1970s, suggested a diet low in fats, sodium, and alcohol and emphasized foods high in carbohydrate and low in sugar. The goals of these recommendations were to prevent disease and meet the body's needs for vitamins, minerals, complex carbohydrates like those found in starchy foods like bread, and dietary fiber.

Today's Dietary Guidelines for Americans (7), published in 1995, suggest a diet with plenty of grain products, vegetables, and fruits. Specifically, these include breads, cereals, pasta, rice, potatoes, corn, dried beans, and all types of fruits and vegetables. The guidelines endorse a vegetarian diet as an alternative healthful way of meeting the recommended dietary allowances (RDAs).

A Firm Foundation

Plant foods like fruits and veggies should be the foundation of your diet. That's not because animal foods are bad for you—it's because plant foods are so good for you. If you eat at least the minimum number of recommended servings per day, you'll be on the road to better health, now and for the rest of your life.

References

  1. Gillman MW, Cupples LA, Gagnon D, et al: Protective effect of fruits and vegetables on development of stroke in men. JAMA 1995;273(14):1113-1117
  2. Manson JE, Willett WC, Stampfer MJ, et al: Vegetable and fruit consumption and incidence of stroke in women, abstract. Circulation 1994;89(2):932
  3. Yu MW, Hsieh HH, Pan WH, et al: Vegetable consumption, serum retinol level, and risk of hepatocellular carcinoma. Cancer Res 1995;55(6):1301-1305
  4. Dorant E, van den Brandt PA, Goldbohm RA, et al: Consumption of onions and a reduced risk of stomach carcinoma. Gastroenterology 1996;110 (1):12-20
  5. Giovannucci E, Ascherio A, Rimm EB, et al: Intake of carotenoids and retinol in relation to risk of prostate cancer. J Natl Cancer Inst 1995;87(23):1767-1776
  6. US Department of Agriculture, Human Nutrition Information Service: USDA's Food Guide Pyramid. Home and Garden Bulletin No. 249, Hyattsville, MD, US Dept of Agriculture, 1992
  7. US Department of Agriculture, US Department of Health and Human Services: Nutrition and Your Health: Dietary Guidelines for Americans, ed 4. Home and Garden Bulletin No. 232, Government Printing Office, 1995

Remember: You, your physician, and your nutritionist need to work together to discuss nutrition concerns. The above information is not intended as a substitute for appropriate medical treatment.

Dr Kleiner is a private nutrition consultant to athletes in the Seattle area. She is a member of the American College of Sports Medicine; a member of the American Dietetic Association and its practice group, Sports and Cardiovascular Nutritionists (SCAN); and a fellow of the American College of Nutrition.


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