Go ahead, try it… put 6 or 7 whole walnuts in your hand, or break them into halves. And then weigh them on a food scale if you want to. It’s about an ounce. But there you have it – a daily serving of a remarkably healthy nut in the palm of your hand!
How healthy are walnuts? The US Food and Drug Administration has approved a qualified health claim[1] that “eating 1.5 ounces per day of walnuts, as part of a low saturated fat and low cholesterol diet and not resulting in increased caloric intake, may reduce the risk of coronary heart disease.”[2]
Wait… what’s that about “not resulting in increased caloric intake”? It’s that old wisdom about “too much of a good thing”. Nuts are “calorie dense” or sometimes referred to as “energy dense”. This means that there are a lot of calories – a lot of energy – in a small serving. So, your 1 ounce handful of walnuts is about 180 calories.
Just so you know, the alternative to “calorie dense” is “nutrient dense”, meaning lots of nutrients but not a lot of calories per serving… like fresh vegetables. But that’s another story.
What makes walnuts so healthy? One of the big benefits is that walnuts may help reduce levels of “bad” cholesterol, known as LDL or low-density lipoprotein cholesterol, which is a key factor in heart health. How? While other nuts are mostly composed of monounsaturated fatty acids, walnuts are primarily composed of polyunsaturated fatty acids (about 13 grams in a 1 ounce serving). Polyunsaturated fatty acids contain significant amounts of alpha-linolenic acid (ALA), which is the plant-based source of omega-3 fatty acids (fish oil is the other main source). The “why and how” of omega-3 fatty acids’ role in your health gets technical pretty fast (you can read about it at the National Institutes of Health web site[3]). So, we’ll stick to stating the benefits: “Besides their nutritional role in the diet, omega-3 fatty acids can help to prevent or treat a variety of diseases, including heart disease, cancer, arthritis, depression, and Alzheimer’s disease, among others...”[4]
Nobody is saying walnuts are some kind of magic food, but still… wow. And remember, your body can’t make omega-3 fatty acids – you have to eat them. So, if you don’t like fish, grab some walnuts!
Now back to that calorie thing for a second…
A new study (released May 2018) conducted by University of Illinois College of Agricultural, Consumer and Environmental Sciences, and published in The Journal of Nutrition, found that your body is only absorbing about 80% of the calorie intake from eating walnuts. It turns out that the other 20% is interacting with microbes in your stomach in very positive ways. In other words, “the way walnuts impact the gut microbiome -- the collection of trillions of microbes or bacteria in the gastrointestinal tract -- may be behind some of those health benefits” of eating walnuts.[5]
Definitely check out the MedicalNewsToday.com citation.[6] It summarizes studies that indicate some of the potential benefits of eating walnuts such as: positive effects on cholesterol levels; cardiovascular health; improved sperm vitality and motility; reduced risk of pancreatic cancer; improved cognitive ability (memory and concentration); and a potential role in protecting against the damaging effects of the protein that forms in the brains of people with Alzheimer’s disease.
There is so much more to say about walnuts and health – like, they are packed with important minerals and vitamins; only 1 gram of sugar; 4 grams of protein; no sodium; no cholesterol; no trans fats… but enough for now…
…just put out your hand, count out 6 or 7 walnuts, and enjoy a really healthy snack!
[1] Qualified health claims (QHCs) are supported by scientific evidence, but do not meet the more rigorous “significant scientific agreement” standard required for an authorized health claim. https://www.fda.gov/Food/LabelingNutrition/ucm2006877.htm
[2] https://www.fda.gov/Food/LabelingNutrition/ucm073992.htm#cardio
[3] https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/
[4] https://www.sciencedirect.com/topics/neuroscience/polyunsaturated-fatty-acid
[5] https://www.sciencedaily.com/releases/2018/05/180503175033.htm
[6] https://www.medicalnewstoday.com/articles/260288.php