March 20, 2000 (Atlanta) -- People concerned about their cholesterol levels no longer have to pass on pecans. Researchers at New Mexico State University have discovered that gobbling down as much as two fistfuls per day of the smooth, oblong nut can lower low-density lipoprotein (LDL) -- the 'bad' cholesterol linked to heart disease.
"We discovered that pecans can have a place in a healthy diet," lead researcher Wanda A. Morgan, PhD, RD, tells WebMD. "Pecans, in balance and moderation with other foods, can help protect us against heart disease." The study appears in the March 2000 issue of the Journal of the American Dietetic Association. The Western Pecan Growers Association funded the study.
According to the National Institute of Health (NIH), a high level of LDL-cholesterol in the blood increases the risk of fatty deposits forming in the arteries, which in turn increases the risk of a heart attack. Thus, LDL-cholesterol has been dubbed 'bad' cholesterol. At the same time, an elevated level of high-density lipoprotein -- HDL or 'good' cholesterol -- seems to have a protective effect against heart disease.
In the pecan study, 19 participants -- roughly three quarters female -- with normal cholesterol levels were divided into a pecan eating group and a control group. The nut eaters ate 88 grams of shelled pecan halves per day for eight weeks. They could choose whether to eat their daily pecan rations as snacks or as part of their regular meals. The pecan eaters were prohibited from eating other nuts, and people in the control group were not allowed to eat any nuts at all. Blood samples to check cholesterol levels were taken at the beginning of the study and at four- and eight-week intervals.
After the first four weeks of the study researchers found the pecan eaters' LDL cholesterol lowered by 10%, although after eight weeks, it was only down 6% from its original level. Morgan says unlike other studies on nuts, participants were allowed to choose what they ate, instead of following a restricted diet. "We wanted to mimic as much as we could what people really did with their daily meals to see if we could still get some of the benefits that were showing up with the other studies," says Morgan, who is an associate professor in the department of family and consumer sciences at New Mexico State University in Las Cruces.
The pecan research is the latest positive study on the benefits of the much-maligned family of tree nuts. In 1999, French researchers reported that people in the Dauphine region of France who frequently consumed walnuts or walnut oil -- typically used in salad dressings -- had higher levels of HDL-cholesterol and another helpful factor associated with cholesterol -- than did people who never ate walnuts.
Also, the American Heart Association reports that in a 12-year study of more than 22,000 doctors in the Physicians Health Study, men whose diets contained high quantities of nuts had a decreased risk of dying from heart disease. "Most nuts are also high in other unsaturated fats and nutrients that might contribute to reduced heart disease risk," says author Christine M. Albert, MD, lead researcher of that study and an instructor at the Harvard Medical School. Albert says they found that nuts contain unsaturated fats, including alpha-linolenic acid, which may help prevent fatal disturbances in the heart's rhythm.
Morgan says some nutritionists and dietitians have long believed that pecans and other tree nuts should be avoided because of their high fat content. She agrees that pecans are high in fat -- more than half of their weight is fat -- but points out that it's mostly the good kind. She says of the 47 grams of fat in a three-quarters of a cup serving, 29 grams is monounsaturated fat, the good fat, and an important part of a balanced diet. Morgan is a licensed dietitian.
While fat from pecans may be OK, calories are another story. Morgan says three-quarters of a cup of pecans contains 459 calories. Still, no significant weight gain was seen among the study participants.
Morgan says that while there have been previous published studies touting the benefits of other tree nuts such as walnuts and almonds, there have not been studies on pecans and blood lipids. "Our research was unique. The good news is our findings on blood lipid profiles is similar to work done by other investigators on other nuts," she says.
Pecans are rich in protein, potassium, zinc, vitamin E, magnesium, carbohydrates, and folic acid, according to the American Dietetic Association, which recommends choosing portions that keep the fat content down and mixing the nuts with other foods to harness the nutrition and flavor of nuts without many calories.
Morgan says future research will focus on smaller amounts of pecan consumption. "We want to find out if the cholesterol benefit carries through at lower levels," she explains.
- New research shows that eating as much as two handfuls of pecans per day can lower levels of LDL, or the bad cholesterol that is associated with heart disease.
- Pecans contain unsaturated fat, including alpha-linolenic acid, protein, potassium, zinc, vitamin E, magnesium, carbohydrates, and folic acid.
- Similar studies have shown that other types of nuts are healthy as well, but consumers should eat nuts in moderation, as they are high in calories.