People no longer need avoid shrimp for its high cholesterol. Steamed shrimp, naturally low in fat, can be included in heart-healthy diets for people without
lipid problems, report scientists from The Rockefeller University and the Harvard School of Public Health in the November American Journal of Clinical
"Most high-cholesterol foods are also high in saturated fats, which people should restrict in their diets. But we found that steamed shrimp, high in cholesterol but very low in fat, do not adversely affect the lipoprotein profile in people with normal cholesterol levels. In fact, if shrimp are substituted for beef or other high fat foods, we predict even more favorable effects," says first author Elizabeth De Oliveira e Silva, M.D., research associate in The Rockefeller University Laboratory of Biochemical Genetics and Metabolism. A meal containing 150 grams, about 5 ounces, of steamed shrimp provides only 1.7 grams of fat, including 0.36 grams saturated fat, and 150 calories, compared to 150 grams of beef, which contains 14 grams of fat, including 4.7 grams of saturated fat, and 390 calories.
Shrimp is second only to tuna fish as the most frequently eaten seafood in the American diet, according to the National Fisheries Institute. Yet despite this
popularity, shrimp has not been previously tested for its effect on lipoproteins in such a meticulous manner, according to De Oliveira e Silva.
Lipoproteins are large molecules that transport fat and cholesterol in the
body. Lipoproteins contain combinations of cholesterol, small proteins and
triglycerides, which include saturated, monounsaturated and polyunsaturated
fats. High levels of low density (LDL) and very low density (VLDL)
lipoproteins contribute to heart attacks by causing atherosclerosis, blockages
of the heart's arteries that affect millions of Americans annually. In
contrast, increases in high density (HDL) lipoproteins reduce the risk for
"We were surprised, but pleased, to find that a low-fat diet with shrimp did not impair lipoprotein profiles," says senior author Jan L. Breslow, M.D.,
Frederick Henry Leonhardt Professor and head of the Laboratory of Biochemical
Genetics and Metabolism at Rockefeller. Breslow, senior physician at The Rockefeller University Hospital, also is president of the American Heart
The scientists suggest the findings stem from, individually or in combination, an inefficiency in absorbing shrimp cholesterol or from minor differences in
the amount and kind of beneficial polyunsaturated fats, called n-3 fatty acids, in the three diets tested. "The slightly higher n-3 fatty acid content in the
shrimp diet might account for the findings of lower triglycerides and higher HDL with shrimp consumption, both of which could be beneficial," explains De
Oliveira e Silva.
In the study, the scientists tested the effects of including shrimp in a low-fat diet among 18 healthy adults who stayed at The Rockefeller University Hospital Clinical Research Center. During the nine-week study, the researchers
randomly assigned each participant to a sequence in which they consumed three diets in rotation for a total of three weeks each: a baseline low-fat diet, the baseline plus shrimp diet and the baseline plus egg diet. The diets were
carefully prepared and weighed to meet each person's caloric needs to maintain weight and provide the same nutritional composition of 15 percent protein, 55
percent carbohydrate and 30 percent fat, including the same quantity of saturated, monounsaturated and polyunsaturated fats.
The diets only differed in the amount of cholesterol. The baseline diet contained only 107 milligrams per day of dietary cholesterol. The shrimp diet
included about 300 grams, or 10 ounces, of shrimp a day, which provided 590
milligrams/day of cholesterol, while the egg diet with two large hard-boiled,
grade A eggs daily contained 580 milligrams/day. The AHA recommends that people
have no more than 300 milligrams of cholesterol each day.
The researchers included a comparison diet using eggs because they are high in
cholesterol. Eggs have, per yolk, 5.1 grams total fat, 1.6 grams of saturated
fat and 213 milligrams of cholesterol. Eggs can increase the level of LDL
level, which raises the risk of heart disease. The AHA recommends that people
restrict eggs to three or four per week.
"Eating shrimp produced lower ratios of total to HDL cholesterol, and of LDL
to HDL cholesterol compared to the egg diet, as well as significantly lower
triglyceride levels than either the baseline or egg diets. Furthermore, the
shrimp diet did not increase levels of heart damaging VLDL cholesterol," says
When compared with the baseline diet, both the shrimp and egg diets produced similar increases in the LDL concentrations, 7.1 and 10.2 percent respectively,
however the shrimp diet tended to increase HDL more than the egg diet, 12.1 and
7.6 percent respectively.
Breslow and De Oliveira e Silva's co-authors include Cynthia E. Seidman, M.S.,
R.D., Lisa Cooper Hudgins, M.D., and Jason J. Tian, Ph.D., from Rockefeller and
Frank M. Sacks, M.D., from Harvard. The National Heart, Lung and Blood
Institute and the National Center for Research Resources, both of the federal
government's National Institutes of Health (NIH), supported the study.
Established in 1910, the Rockefeller University Hospital is the oldest in the
United States devoted solely to experimental medicine. The hospital links
laboratory investigations with bedside observations to provide a scientific
basis for disease detection, prevention and treatment. This special hospital
environment served as the model for the Warren G. Magnuson Clinical Center,
opened at the NIH in 1953, and similar facilities supported by federal funding
at more than 75 medical schools in the United States.