Once thought of as high calorie treats to be avoided, nuts and seeds are emerging as an important component of a healthy dietary pattern.
All Seeds: Nuts and seeds are a rich source of plant protein, have plenty of dietary fiber, and are high in heart-healthy mono-and polyunsaturated fats (including plant omega-3 fatty acids) and low in saturated fats. They also contain many vitamins and minerals (such as vitamin E, magnesium, phosphorus, copper, and manganese) and a collection of plant chemicals with potential antioxidant and anti-inflammatory properties.
Nuts and seeds are often thought of as separate categories, but they are actually all seeds of flowering plants. What we call seeds (like sunflower, flax, chia, and pumpkin seeds) come from flowers and crops. Nuts are seeds of trees. Common nut varieties include almonds, cashews, macadamias, pistachios, and walnuts. Peanuts are not technically nuts—they are legumes like beans, lentils, and peas—but they are nutritionally similar to tree nuts and commonly treated as nuts.
Health Impact: Frequent nut consumption is associated with a lower risk of developing high blood pressure, cardiovascular disease (CVD), and cancer, and evidence from clinical trials has suggested nut consumption may improve cholesterol and triglyceride levels, insulin resistance and oxidative stress.
Swapping less nutritious foods with nuts and seeds may be an impactful dietary change. In a study by Tufts’ researchers that looked at the association between various dietary factors and death from heart disease, stroke, and type 2 diabetes in the U.S., low intake of nuts and seeds was more strongly associated with these diet-related deaths than any dietary factor except high intake of sodium.
If you don’t eat nuts, it’s not too late to start incorporating them into your diet. A large observational study published recently in the Journal of the American Heart Association found that replacing less healthful food items with nuts was associated with a subsequent lower risk of CVD over time (the study did not look at seed intake). Compared with participants who made no changes to their nut intake over the 26-year study period, increasing total nut consumption by even half an ounce per day was associated with a lower risk of overall CVD, coronary heart disease, and stroke, particularly when nuts were eaten in place of meat, processed meats, refined grains, French fries, and sweets.
A 2019 study showed that people who increased nut consumption after they were diagnosed with type 2 diabetes had an 11 percent lower risk of CVD, 15 percent lower coronary heart disease risk, 25 percent lower risk of death from CVD, and 27 percent lower risk of death from any cause compared to those who did not change nut consumption after
Seeds have also been associated with health benefits. A 2019 review of research published in the journal Nutrients cites studies in which various levels of flaxseed consumption have been associated with a number of health benefits, including decreased risk of cardiovascular disease, cancer (especially breast cancer) and diabetes. In a double-blind, placebo-controlled, randomized trial, participants with peripheral artery disease were fed a variety of foods (bagels, muffins, bars, buns, pasta, cookies) that contained 30 grams of ground flaxseed or a placebo every day for six months. Those eating the flaxseed products had significant decreases in blood pressure compared to the group who was given a placebo. (This effect may have been due to the flaxseed specifically, or the additional fiber the flaxseeded provided.)
Nuts and seeds are high in fats relative to most other plant foods, but the majority of these are mono- and polyunsaturated fats, which have been associated with numerous health benefits when consumed in place of saturated fats or refined carbohydrates. Nuts and seeds are particularly rich sources of the plant omega-3 fatty acid, alpha linolenic acid (ALA).
A Weighty Matter: It was once a common belief that nut and seed intake cause weight gain, but this is not supported by research. In fact, some data show that nut consumption may actually benefit weight control by helping to regulate appetite and discourage less healthful choices. In a study published in a 2020 issue of the journal Appetite, providing healthy women with a daily intake of 44 grams of pistachios improved their diet quality without affecting body weight. The women in this study reported decreased hunger and an increased feeling of fullness with the addition of the nuts to their diet, which resulted in lower consumption of carbohydrates and starches. Studies on other types of nuts and peanuts have yielded similar results.
Mix it Up: Include nuts and seeds in your diet. Choose lightly salted or no salt varieties and skip or limit those with added sugars or coatings (like chocolate). “Rather than simply adding nuts and seeds to one’s diet, it is important to eat them in place of other foods,” says Alice H. Lichtenstein, DSc, the Gershoff professor at the Friedman School and executive editor of Tufts Health & Nutrition Letter. “Try them in place of refined carbohydrate snack foods like pretzels and crackers, and sweets such as candy and cookies.”
The Healthy U.S. Style Eating pattern recommends non-vegetarians on a 2,000-calorie diet aim for five servings of nuts and seeds per week. A “serving” is defined as one half-ounce of nuts or seeds (less than a palmful), or one tablespoon of nut butter.
It’s easy to incorporate nuts and seeds into your diet with simple, healthy substitutions, like these:
- Enjoy a handful of nuts and seeds instead of processed snacks and sweets
- Substitute nuts in place of croutons
- Bread fish or poultry or top casseroles with ground or finely chopped nuts instead of breadcrumbs
- Replace half or all of the chocolate chips in cookies and muffins with nuts
- Switch out some of the red meat in burgers or meatloaf with ground nuts
- Skip some or all of the meat and stir fry nuts with vegetables
While there are no “superfoods,” nuts and seeds are a delicious, satisfying, versatile, and healthy type of food to swap in to one’s diet.