It will come as no surprise to anyone reading this that diet-based health conditions are a major concern in the United States.
Both of these increase the risk of cardiovascular disease, which is a leading cause of death worldwide.
Because diet plays such a pivotal role in the development of conditions that impact heart health, researchers are on the case.
The race is now on to locate simple dietary interventions that may help to prevent obesity and diabetes, halt their progression, or — in an ideal world — reverse them.
The benefits of nuts
Among foods that have shown promise are nuts in general. These healthful, nutrition-dense food items contain "good" fats, omega-3s, and a whole host of micronutrients.
A wide-ranging review — published in 2016 — concluded, "Higher nut intake is associated with reduced risk of cardiovascular disease, total cancer, and all-cause mortality, and mortality from respiratory disease, diabetes, and infections."
The findings are impressive, but it is worth noting that nuts may not be able to take all of the credit. For instance, someone who consumes nuts regularly might be predisposed to eating higher levels of natural and fresh foods, overall.
On the other hand, someone who eats virtually no nuts may also eat smaller quantities of other fresh foods. Herein lies the problem with studying the impact of a single food on a population: everyone is different and so are their eating habits.
It is difficult to separate one single food item from the whole picture. Although this pill needs to be swallowed, many studies have reported significant benefits of diets that contain nuts. As another example, a study that included dietary data from well over 100,000 people concluded:
"[H]igher consumption of total and specific types of nuts was inversely associated with total cardiovascular disease and coronary heart disease."
Today, in the wake of numerous trials, it is pretty well-established that nuts, in moderation, are a welcome addition to a well-balanced diet.
Drilling into the pecan
A number of nut types have been individually assessed for their health benefits. The most recent study in this field, now published in the journal Nutrients, focused on the benefits of pecans on cardiovascular health.
This new research was carried out at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Medford, MA.
To avoid the issues that would accompany generalizing diet across a whole population, the latest study carefully controlled the participants' diet. This meant that the researchers could add a daily handful of pecans to a standard U.S. diet and view the effects of the nut in relative isolation.
However, the downside to this approach is that it could only be carried out on a small sample: 26 men and women.
Each participant — all of whom were overweight or obese but otherwise healthy — spent 4 weeks on one diet then switched to spend the remaining 4 weeks on another diet.
One was a control diet and the other one was roughly the same, except that 15 percent of the total calories were replaced by pecans in the latter. Both diets were low in fiber, fruits, and vegetables. Calorie content, total fat, and carbohydrate levels were kept the same.
It was found that the addition of pecans to the participants' diets improved insulin sensitivity. Also, there was a positive impact on other markers of cardiometabolic disease — namely, changes in serum insulin and the function of beta cells, which store and release insulin.
"Pecans are naturally high in monounsaturated and polyunsaturated fats, so replacing a portion of the saturated fat in the diet with these healthier fats can explain some of the cardioprotective effects we observed."
Lead researcher Diane McKay, Ph.D.
She goes on, "But, pecans also contain a number of bioactive plant compounds as well as vitamins and essential minerals that all likely contributed to this benefit. What's really interesting is that just one small change — eating a handful of pecans daily — may have a large impact on the health of these at-risk adults."
A note of caution
While the results are encouraging, much more work will need to be carried out on a larger sample before drawing firm conclusions. It is also worth pointing out that the research was funded by the National Pecan Shellers Association (NPSA), whose mission it is "to support and promote the interests of pecan shellers."
Science is, of course, a slow accumulation of evidence from a number of studies across time, and investigating the potential health benefits of pecans is no different.
The authors do cite previous studies looking at pecans' effects on health, but in many cases, these projects were also supported by the NPSA. And, although benefits were shown in such trials, they were often carried out on a small scale.
Of course, the new research is published in a respected journal and was carried out at respected institutions, but one must bring some healthy skepticism to the table.
As evidence mounts, it seems that a diet rich in nuts is beneficial to health in general. However, at this stage, the specific benefits of pecans will need further investigation. If they truly do reduce cardiovascular risk in overweight people, pecans would be a low-cost, natural intervention.