Diet is key weapon in fight against 4 common diseases

Nancy Stohs and Karen Herzog
Milwaukee Journal Sentinel
Dec. 1, 2003 12:00 AM

When you have a bacterial infection, you get an antibiotic. When you want to give up smoking, you get a nicotine patch. If you could do something to lower your risk of cancer, heart disease or other serious ailments, why wouldn't you do it?

Because you might not like the prescription: Lots of fruits and vegetables. Fish. Milk. Limited amounts of red meat. And plenty of exercise.

The list of "good" and "bad" foods seems to change from week to week, which can make us want to throw up our hands and say, "Fine. I'll eat whatever I want."

But in fact, for some common life-threatening diseases, the link to diet is strong and well documented.

Here's a look at four such diseases: cancer, heart disease, diabetes and osteoporosis. In each case, the right dietary choices can at least minimize the risk of developing the condition, if not outright prevent it.

Cancer

For the majority of Americans who don't smoke, eating a healthful diet and being physically active can reduce cancer risks, according to the American Cancer Society.

Evidence suggests that one-third of the 550,000 cancer deaths in the United States each year are a result of unhealthy diet and lack of physical activity.

The American Institute for Cancer Research recommends a mostly plant-based diet of fruits, vegetables, whole grains and legumes, with a reduced emphasis on meat.

A low-fat diet that includes a wide variety of at least five servings of fruits and vegetables daily can decrease overall incidence of cancer by 20 percent, according to the institute. The case is even stronger with colorectal cancer, for which the main causes are believed to be diet and related factors, though much more is known about colon than about rectal cancer, according to the American Institute for Cancer Research.

Research suggests up to half of colorectal cancers could be prevented by diets high in vegetables and low in fat. Colon and rectal cancers are not the same, but usually are categorized together.

Heart disease

The No. 1 killer of Americans, and a key cause of disability, is cardiovascular disease, including heart disease and stroke.

Heart disease is the No. 1 killer and stroke is No. 3. About 62 million Americans live with cardiovascular diseases, according to the American Heart Association.

Cardiovascular diseases cost Americans more than any other disease - a projected $352 billion in medical expenses and lost productivity this year.

Artery-clogging cholesterol is the most widely publicized culprit in the risk of cardiovascular disease and 42 million Americans have high cholesterol, the association reports.

Dietary cholesterol - found in foods such as eggs and red meat - should be limited to no more than 300 mg per day for the average person and less than 200 mg for people at risk.

The heart association recommends eating lots of fruits and vegetables, which are good sources of vitamins, minerals and fiber, but have few calories, little fat or sodium and no cholesterol.

The association's dietary recommendations are: at least five servings of fruits and vegetables daily; six or more servings of whole grains and beans; a varied diet including the major food groups; and at least two servings per week of fatty fish, such as tuna or salmon.

The association recommends a diet moderate in sugar, because of the link between obesity and high consumption of sweets.

Diabetes

About 17 million people in the United States, or 6.2 percent of the population, have diabetes, according to the American Diabetes Association. An estimated 11.1 million have been diagnosed; about 5.9 million are unaware they have the disease.

The best dietary advice in the quest to fend off diabetes is simply this: Lose weight if you're overweight and follow a diet that permits you to maintain a healthy weight.

Overweight, along with family history, are the biggest risk factors for diabetes. It's also important to stay active. "We are really trying diligently not to separate those two," said Marian Benz, a registered dietitian and certified diabetes educator in Milwaukee.

The concern about being overweight extends to children, who are exhibiting in adolescence a new type of diabetes, Benz said - not Type 1 (insulin-dependent, previously known as juvenile diabetes) or Type 2 (non-insulin dependent).

Children's Hospital of Wisconsin now works with about 100 children with this new type, called maturity-onset diabetes of youth. While much is unknown, it is believed that this form of diabetes is caused by excess weight and may be preventable through diet and weight control.

Osteoporosis

About 10 million people (80 percent of them women) are estimated to have osteoporosis. It is responsible for more than 1.5 million fractures annually, according to the National Osteoporosis Foundation.

The dietary prescription for reducing risk is simple and well-documented: high intake of calcium, protein and vitamin D. Calcium and protein each make up about half the volume of bone; by weight, protein is about one-third, said Robert P. Heaney, professor of medicine at Creighton University in Omaha, Neb.

In one recent study, the lowest rate of bone loss was found in women with the highest protein intake and vice-versa. There was a fourfold difference.

"We focus on calcium because it is the nutrient more likely to be deficient in the American diet," Heaney said. "(However,) my suspicion is that a substantial fraction of the American population today (also) does not get enough protein."

Throughout our lives, bones are constantly changing, or "remodeling," to adapt to changing uses and demands or to make repairs. Bones can recycle stored calcium and phosphorus but not protein.

"So we need a fresh supply of dietary protein every day," Heaney said.

Meat and plant proteins are equally effective.

The third key nutrient, vitamin D, is needed to absorb an adequate amount of calcium.

"What people don't realize is how prevalent vitamin D deficiency is in North America," Heaney said.

A 1998 study of 290 patients admitted to Massachusetts General Hospital found 57 percent to be deficient in vitamin D. By current standards subscribed to by researchers, Heaney said, it would be more like 85 percent.

Vitamin D is added to milk, and "a couple of boutique yogurts may have it added. (Otherwise), unless you eat a lot of fish oil, or get plenty of sun exposure, you aren't going to get enough" and supplements may be necessary, he said.

Specific recommendations for these nutrients are:


• Calcium: The RDA differs by age and gender, from 800 to 1,500 mg a day, but those are really "the least you can get by on," according to Heaney. He advises everyone from adolescents on up to consume 1,200 to 1,500 mg each day.


• Vitamin D: The latest recommendations call for 200 International Units a day to age 50, 400 IU to age 70 and 600 IU after 70. Heaney routinely prescribes 1,000 units per day.


• Protein: 0.8 gram per kilogram of body weight. (Multiply your weight in pounds by 0.45 to find your weight in kilograms.) By this measure, a weight of 150 pounds calls for a diet with 54 g of protein daily. Some experts believe this isn't high enough, Heaney said.