Editor’s note: The Focus on Research column highlights different research projects and topics being explored at Penn State. Each column will feature the work of a different researcher from across all disciplines.
For centuries, Valentine’s Day has symbolized one of the most romantic days of the year. As far back as the 18th century in England, people showed their love by giving flowers, candy and greeting cards — known as “valentines” — and today the tradition continues. But February is about more than celebrating Valentine’s Day — February is American Heart Month. And, yes, it is possible to keep your sweetheart happy and their heart healthy — and yours, too.
Research conducted by nutritionist Penny Kris-Etherton and her team at Penn State found that a diet containing about one ounce of dark chocolate per day prevents bad cholesterol from oxidizing, a process that may lead to heart disease, and increases good cholesterol. There is also substantial evidence to suggest a beneficial effect of dark chocolate on blood pressure, lipids and inflammation. Combine these findings with Kris-Etherton’s discoveries on the heart-healthy benefits of nuts and your heart just may skip a beat — in a good way.
In her most recent research on almonds, Kris-Etherton found that individuals consuming a diet containing 1.5 ounces of almonds versus the same diet containing a healthy muffin experienced greater reductions in LDL-C (some of the bad cholesterol) and non-HDL-C (all of the bad cholesterol), while keeping their HDL-C (good cholesterol) levels high. Nut consumption also helped boost reverse cholesterol transport — when HDL particles remove fatty plaque buildup from the arteries and transport it to the liver where it is degraded. Research has shown that this process reduces your risk of heart disease.
Penn State’s clinical findings are consistent with several population studies conducted in the U.S., which have shown that consuming nuts and peanuts five times per week or more lowers the risk of coronary heart disease by about 40 percent. Likewise, adding 30 grams of nuts per day (a little more than an ounce) to a Mediterranean diet lowers risk of heart disease by 30 percent. And in one of the largest studies to date, results from nearly 120,000 participants in the Nurses’ Health Study and the Physicians’ Health Study showed that during 30 years of follow-up daily nut-eaters were less likely to die of cancer, heart disease and respiratory disease. Overall, the daily nut-eaters were 20 percent less likely to have died during the course of the study than those who avoided nuts. Essentially, people who ate nuts every day lived longer, healthier lives than people who didn’t eat nuts.
Like many others, I once condemned nuts as being too high in fat, but since joining the Kris-Etherton research team, I too have gone nuts. Thus, I want to reassure weight-conscious readers that, when consumed in reasonable quantities, nuts are not fattening and can even help people lose weight and maintain their weight loss. As part of her most recent study, Kris-Etherton found that in addition to the beneficial effects on heart health, after just six weeks of consuming 1.5 ounces of almonds per day, individuals experienced reductions in abdominal fat — the most dangerous kind — despite having no significant change in body weight. Likewise, other clinical trials have found that adding nuts to the diet did not affect body weight. But more important, participants in studies that included nuts in a weight-loss regimen lost more weight and ended up with a smaller waist and less body fat than participants who did not eat nuts.
One explanation for the weight control benefit of nuts is the satiation provided by their relatively high fat and protein content, which may reduce snacking on sweets and other carbohydrate foods. Another is that all the calories in nuts, especially whole nuts, may not be absorbed because they resist breakdown by enzymes in the body. A recent study reported that the metabolizable energy content, or energy available to the body, of walnuts was 21 percent less than the calculated value. These findings are consistent with studies of other nuts (almonds and pistachios) and may help to explain why people who eat nuts do not weigh more than people who do not eat nuts. In fact, frequent nut consumption has been associated with a reduced risk of weight gain.
This begs the question — would a combination of dark chocolate and nuts exhibit a synergistic effect on cardiovascular disease risk factors? Soon we will have your answer. Kris-Etherton and her research team have just completed the feeding portion of a clinical trial examining this very question. In this study, participants consumed one of four diets: a standard control, an almond diet, dark chocolate diet, or a combination of dark chocolate and almonds. The analyses are currently being conducted and the results will be presented later this year.
Nutritionally, both nuts and dark chocolate contain bioactive substances that may have beneficial effects on heart health. So, treat your heart and your sweetheart’s heart to some of their favorite nuts along with some dark chocolate ... or better yet, try cocoa-dusted or chocolate-dipped nuts. It’s okay to go a little nuts in the pursuit of heart health this month, and to celebrate your love on Valentine’s Day.
Jennifer Fleming is an instructor and clinical research coordinator in Penn State’s College of Health and Human Development. Penn State distinguished professor of nutrition Penny Kris-Etherton contributed to this article.