Further evidence to suggest that almonds could benefit our health hit the press this week as scientists in Canada report that almonds significantly lowered bad cholesterol levels in a study of people with high cholesterol.
Canadian researchers conducted the study in order to determine if, and at what level of consumption, almonds could help reduce heart disease risk by lowering high cholesterol.
Previous research has suggested that nut consumption could reduce the risk of coronary heart disease. However eating more nuts increases calories, and therefore is generally not recommended for people who need to restrict calories.
For the study 27 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 decilitre (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 than 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, wholewheat 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, explained lead author David Jenkins, director at the Clinical Nutrition and Risk Factor Modification Center, St. Michael's Hospital, Toronto. The only difference being that the monounsaturated fat was swapped for the starch in the muffin, he said.
Researchers measured cholesterol levels, blood pressure and weight in the subjects. They found that patients reduced the low-density lipoprotein (LDL - bad cholesterol) by an average of 4.4 per cent with the half portion of almonds and 9.4 per cent with the full portion.
"We were quite impressed," said Jenkins. "If you look at the ratio of LDL to HDL (high-density lipoprotein, the good cholesterol), the reduction was 7.8 per cent for the half dose and 12 per cent 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 said 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 (eg. almonds, pecans, walnuts).
Jenkins added that nuts, including almonds, walnuts, pecans, peanuts, macadamia and pistachios, have been shown to lower blood cholesterol. He maintained that the combination of monounsaturates with some polyunsaturates in nuts is an ideal combination of fats and that although there is not enough research to say that all nuts are equal in their health value, almonds have particularly well researched profiles.
"This study suggests that replacing carbohydrates with monounsaturated fat - within the context of a diet that is low in saturated, trans-fat and cholesterol - favourably affects cholesterol levels and cardiovascular risk," said Alice Lichtenstein, vice-chairman of the American Heart Association nutrition committee.
Full findings are published in the latest issue of Circulation: Journal of the American Heart Association.