NEWSWISE/Medical News
Almonds significantly lowered bad cholesterol levels in
a study of people with high cholesterol reported in today's rapid access
issue of Circulation: Journal of the American Heart Association.
Canadian researchers conducted the study,
funded by The Almond Board of California and the Canadian government, to
determine whether almonds can help reduce heart disease risk by Lowering
high cholesterol and at what consumption level.
Some previous research has suggested that
nut consumption reduces the risk of coronary heart disease. Because
previous research has suggested that eating more nuts increases calories,
nuts generally are not recommended for people who need to restrict
calories.
Twenty-seven high cholesterol patients
(15 men and 12 postmenopausal women, average age 64) completed the
three-phase study. Their average total cholesterol level was 260
milligrams per deciliter (mg/dL) at baseline.
Three one-month diets were undertaken.
For one month each participant ate a full dose of almonds (average 74
grams), which represented a little less that one quarter of their total
daily caloric intake. For one month they took a half dose of almonds
(average 37 grams) -- described as a "handful" of almonds. In the last
month, they ate a low-saturated fat, whole-wheat muffin as a daily snack.
The muffin snack served as the control
diet because it had about the same amount of calories, protein and
saturated and polyunsaturated fats, explains lead author David J.A.
Jenkins, M.D., director at the Clinical Nutrition and Risk Factor
Modification Center, St. Michael's Hospital, Toronto. The only difference
was that the monounsaturated fat was swapped for the starch in the muffin,
he says. Jenkins is also Canada Research Chair in Nutrition and Metabolism
at the University of Toronto.
Researchers measured cholesterol levels,
blood pressure and weight in the subjects. They found that patients
reduced low-density lipoprotein (LDL -- bad cholesterol) an average 4.4
percent with the half portion of almonds and 9.4 percent with the full
portion.
"We were quite impressed," says Jenkins.
"If you look at the ratio of LDL to HDL (high-density lipoprotein, the
good cholesterol), the reduction was 7.8 percent for the half dose and 12
percent for the full dose by the fourth week. That ratio is very important
in assessing cardiovascular risk."
The patients' cholesterol levels did not
significantly drop after the muffin phase.
Jenkins says that practitioners should
encourage patients to eat almonds as part of a healthy balanced diet as
long as they are natural or "dry roasted" without added oils or salts.
Nuts do not have cholesterol and are a
good source of protein, according to the American Heart Association.
However, the association stresses that the potential benefits of nuts may
be negated if they are added rather than substituted for other foods in
the diet. While nuts and seeds tend to be very high in fat and calories,
most of the fat is polyunsaturated or monounsaturated (e.g. almonds,
pecans, walnuts).
Participants in this study were carefully
counseled on how to use nuts in place of other foods in the diet.
Nuts, including almonds, walnuts, pecans,
peanuts, macadamia and pistachios, have been shown to lower blood
cholesterol, Jenkins says. The combination of monounsaturates with some
polyunsaturates in nuts is an ideal combination of fats, he says.
Although, there is not enough research to say that all nuts are equal in
their health value, almonds have particularly well researched profiles, he
says.
"This study suggests that replacing
carbohydrates with monounsaturated fat -- within the context of a diet
that is low in saturated, trans fat and cholesterol -- favorably affects
cholesterol levels and cardiovascular risk," says Alice Lichtenstein,
D.Sc., vice-chair of the aociation's nutrition committee.
Almonds are a good source of
monounsaturated fat and potentially other beneficial compounds. The
American Heart Association recommends eating an overall balanced diet that
is high in fruits, vegetables and whole grains, and includes low-fat dairy
products, fish and lean meats. Whenever any dietary change is made, care
must be taken to avoid increasing total caloric intake, Lichtenstein says.