Scientific Update

UK Health Department Calls for Some to Decrease Consumption of Red and Processed Meat

In March 1998, the British Health Department recommended that those adults eating more than the average amount of red and processed meat-especially those eating a lot more-should reduce consumption in order to avoid cancer. Average consumption of these products is around 90 grams (3 ounces) daily with higher consumers eating 140 grams (4.5 ounces) or more per day.

Women at High Risk for Breast Cancer May Benefit from Reducing Meat Intake and Increasing Vegetable Intake

Researchers have found that oxidative DNA damage in blood may be a marker for increased cancer risk. Healthy women who had a close relative with breast cancer were examined to determine whether or not certain foods were associated with oxidative DNA damage. Overall, meat intake was associated with DNA damage and higher intake of vegetables was associated with lower risk of DNA damage. There appeared to be more benefits from eating cooked as compared to raw vegetables although the researchers speculate that this may be due more to the type of vegetable that is usually eaten raw (like lettuce) and not to the cooking process itself. They recommend that if their results are confirmed in larger studies, women with a family history of breast cancer should make specific dietary changes including reduced meat intake and increased vegetable intake.

But I Just Ate an Hour Ago!

Do certain protein sources have a more satiating effect? This was the question which was asked by researchers in France and Belgium. They studied 12 subjects who ate a lunch containing the same amount of calories, fiber, fat, and carbohydrate but which had different protein sources. Subjects rated their feelings of hunger and fullness for the next 8 hours and their energy intakes were measured for 24 hours. Regardless of the protein source, there was no difference in hunger feelings in the afternoon, nor did subjects in one group eat any more than other subjects did over the next 24 hours. The protein sources tested were egg, cow's milk, gelatin, soy, pea, and wheat. So, protein source does not appear important in satiety as long as calorie intake is similar.

Vegetarians Have Lower Risk of Dying from Heart Disease Than Non-Vegetarians

Data from 5 studies of vegetarians conducted in the US, the UK, and Germany were combined and examined to see if vegetarians were more or less likely to die from heart disease, stroke, and several kinds of cancer than were non-vegetarians. More than 76,000 men and women aged 16-89 years were studied an average of almost 11 years. The main finding of the study was that vegetarians were much less likely than non-vegetarians to die from heart disease. This was especially true in those subjects below age 65. The reduction in risk was seen in those who had been vegetarian for more than 5 years. A vegetarian diet was not associated with any reduction in risk of dying from stroke, colorectal cancer, breast cancer, prostate cancer, lung cancer, or stomach cancer although there were fewer deaths overall from cancer so the study was not able to assess whether or not there was a moderate decrease in deaths associated with vegetarianism. However, because of the large number of subjects in this study, the results with respect to heart disease are intriguing and point to a vegetarian diet as an important step in reducing risk of dying from heart disease.

Teen Vegetarians

In 1986-87, more than 100 adolescents in non-urban Minnesota who reported they were vegetarians were compared with non-vegetarian teens. Nineteen percent of vegetarians were male and 81% were female. A higher percentage of minority teens identified themselves as vegetarians than did white teens.

Vegetarian teens were twice as likely to consume fruits or vegetables, one third as likely to consume sweets, and one fourth as likely to eat salty snack foods more than once a day. These were health supporting behaviors by vegetarian teens.

On the other hand, vegetarian teens were more likely to practice dieting, use laxatives, and exhibit other behaviors often linked to eating disorders. While the frequency of these behaviors in this group of teens certainly points to a need to check for adequate food intake in vegetarian teens, we cannot conclude that vegetarianism was the cause of the disordered eating. It is more likely that vegetarianism, in some teens, was just another way to limit food intake.

Notes of Interest ...

• The Centers for Disease Control recently released new recommendations to prevent and control iron deficiency in the United States. They point out that iron deficiency in infancy and early childhood can be prevented through breastfeeding, use of iron-fortified formula, and appropriate consumption of iron-rich foods (such as iron-fortified infant cereal). Consumption of more than 3 cups of cow's milk daily after the first year of life increases the risk of iron deficiency. MMWR 1998. 47[No. RR-3]:1-29.
• Although adults in the US have dramatically lowered the percent of calories from fat in their diets over the last 3 decades (from 45% of calories in 1965 to about 34% in 1995), there has been little change in total fat consumption since 1989. This is because people are taking in more calories, largely from increases in soft drinks, alcohol, and grain products. Thus, fat consumption is not decreasing in the US among adults. USDA Center for Nutrition Policy and Promotion, April, 1998.
• The top five sources of calories for US adults are yeast bread, beef, cow's milk, baked goods like cakes and cookies, and soft drinks. Top fat sources are beef, margarine, salad dressings, cheese, and cow's milk. Top cholesterol sources are eggs, beef, poultry, cow's milk, and cheese. Top fiber sources are yeast bread, ready-to-eat cereal, dried beans, potatoes, and tomatoes. Top iron sources are ready-to-eat cereal, yeast bread, beef, baked goods like cakes and cookies, and pasta. J Am Diet Assoc 1998; 98: 537-547.