Nuts are defined as dry, single-seeded fruits with a high oil content, enclosed in a tough outer layer. Many seeds also fall into this category (such as sunflower and safflower). Some, like peanuts, fit more than one description (both a legume and seed). For the purpose of simplicity, in this article we will include all species commonly referred to as "nuts" and "seeds," regardless of their specific category.
Nuts and seeds were an important energy and nutrient source throughout history. Almonds and pistachio nuts are mentioned as far back as biblical times, and references to other nuts and seeds abound in the literature. Historians hypothesize that ancient societies (about 10,000 years ago) centered on the harvesting of nuts, which may then have fostered agriculture. Predictable growth (nuts grow on trees), long storage life (especially during winter), and generous nutrient profiles are all advantages of nuts to ancient cultures. Interestingly, ancient Romans gave sugared almonds as gifts at weddings, and this custom is still used today. Peanuts, which date back to about 800 B.C., much later joined the Apollo astronauts to the moon in 1969 (1).
Nuts and seeds are extremely nutrient-dense. They provide generous amounts of calories, fats, complex carbohydrates, protein, vitamins, minerals and fiber. Trace minerals like magnesium, zinc, selenium and copper are important but may be under-consumed in today's largely processed Western diet, and even in some plant-based diets. Nuts and seeds are a reliable and delicious source of these essential nutrients. Plus, more than just a way to meet basic nutrient needs, nuts and seeds have been shown to protect against disease. Phytochemicals, bioactive compounds that help fight illness, in nuts and seeds include ellagic acid, flavonoids, phenolic compounds, luteolin, isoflavones and tocotrienols. Nuts also contain plant sterols, thought to help keep cholesterol levels in check and reduce cancer risk.
A detailed chart comparing nutrient values of nuts can be viewed at nuthealth.org/nutrition, followed by /nutrient1oz.html for a general nutrient comparison, /phytochemical.html for a list of known phytochemicals, and /orac.html for selected antioxidant values in nuts. A few nut nutrient notables: Brazil nuts are the highest food source of the essential mineral selenium. Cashews have more iron than other nuts. An ounce of pine nuts has more manganese than even the RDA. Sunflower seeds are the richest source of vitamin E. And pistachios are by far the best nut source of lutein, a phytochemical important for eye health. Eating a variety of nuts and seeds daily ensures that you're getting a healthy balance of these and other important nutrients.
It's no longer a secret that nuts and seeds are healthful, but it's a shame that these little nutritional gems got such a bad rap for so long (mostly because of their relatively high fat content). But even the U.S. government is jumping on the bandwagon and encouraging us to eat more. In 2003, the FDA approved a health claim for nuts and heart disease, which is a big deal: "Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease." Unfortunately, seeds don't get as bright a spotlight as nuts, and they really deserve to.
Much to the chagrin of us vegans and vegetarians, the USDA continues to lump nuts and seeds in the same food group as meats, poultry and fish, reasoning that they are all good protein sources. In some ways, it is unfortunate that nuts and seeds appear to rank equally with animal flesh. Meat is known to damage health (not to mention other problems with meat), and nuts and seeds are known to protect health. And their origins could not be more opposite. But in other ways, referring to nuts and seeds as an equally acceptable protein source might be a good thing. Since plant foods are often viewed as inferior to animal foods, grouping peanut butter and steak together grants the assumption that these foods are, at least to an extent, interchangeable. After all, ounce per ounce, the protein content of nuts is comparable to meat.
A closer look at the USDA's 2005 Dietary Guidelines and Food Guide Pyramid reveals that nuts and seeds are actually recommended along with fish for their healthy oils. In fact, the MyPyramid Web site states, "Fish, nuts, and seeds contain healthy oils, so choose these foods frequently instead of meat or poultry." The site also states, "Some nuts and seeds (flax, walnuts) are excellent sources of essential fatty acids, and some (sunflower seeds, almonds, hazelnuts) are good sources of vitamin E." If we could move this information out from under the muddle and make it more available to people, perhaps folks would consume more nuts and seeds and less animal flesh, benefiting overall health.
As vegans, we should follow not the UDSA or FDA nutrition guidelines, but the Vegetarian Pyramid and Vegetarian Food Guide that accompany the American Dietetic Association's Position Paper on Vegetarian Diets. Here, nuts and seeds are part of the "Legumes, Nuts, and Other Protein Rich Foods" Group (five servings recommended). The Guide states, "Include two servings every day of foods that supply omega-3 fats. Foods rich in omega-3 fat are found in the legumes/nuts group and in the fats group. A serving is 1 teaspoon (5 mL) of flaxseed oil, 3 teaspoons (15 mL) of ground flaxseed or 1/4 cup (60 mL) walnuts. For the best balance of fats in your diet, olive and canola oils are the best choices for cooking." Further, "Servings of nuts and seeds may be used in place of servings from the fats group." (2)
How many servings of nuts and seeds should we aim for per day? This depends on the rest of your diet. The Vegetarian Food Guide recommends five servings of high-protein foods and two servings of fats, and nuts and seeds can fall into either group. A reasonable goal might be two total servings, adjusting the remaining servings of protein and fat. (A serving of nuts or seeds is 1 ounce, or 2 tablespoons of nut/seed butter.)
Most studies on the health effects of nuts and seeds show benefits related to cardiovascular (heart/blood) health, possibly because of their high ratio of unsaturated to saturated fat, their high fiber content, their antioxidant and phytochemical content, or perhaps how all of these factors work together in the body. This is big news, as cardiovascular disease is the number-one killer in the United Sates. And while the majority of studies focus on nuts, it is likely that the relationship of seed consumption to health are similar, due to the similar nutrient profile and origin of each.
Direct cross-cultural comparisons reveal that in countries where people eat a lot of nuts, the incidence of cardiovascular diseases is lower than in countries where people eat few nuts. Controlled studies show similar relationships; not only have nuts been shown to lower cholesterol levels, but to decrease risk of actual disease and death. In a study of more than 34,000 Seventh-Day Adventists, those who consumed nuts at least five times a week had half that rate of heart attack as those who rarely ate them, and those who ate nuts only once a week still had a 25 percent lower risk of heart disease than nut avoiders (3). Another study of 34,500 women showed that those who ate nuts were 40 percent as likely to die from heart disease as those who never ate nuts (4). More recently, the Nurses' Health Study, involving over 86,000 women, reported a lower rate of heart disease among frequent nut consumers than for nut avoiders (5).
While dozens of studies have compared nut consumption to cardiovascular health outcomes, it is difficult to draw conclusions because of the different study designs, different nuts studied and different populations involved. In 2005, researchers compiled data from 23 studies (including studies on almond, peanut, pecan, walnut and macadamia consumption) and concluded that 1.5 to 3.5 servings of nuts per week, as part of a heart-healthy diet, significantly decreased total and LDL (bad) cholesterol levels (6). Since this summary was published, at least two studies suggest similar benefits for pistachios (7, 8). For heart health, it seems that you can't go wrong with nuts.
Despite its reputation of a high-calorie and -fat snack, nuts and seeds may play an important role in weight loss and maintenance. How? Mostly, by curbing appetite. Nuts are thought to promote satiety, which can help reduce the consumption of other foods (9). Indeed, a recent review showed that frequent nut-eaters are no heavier than nut avoiders (10). A study of 65 people on a weight reduction program in 2003 compared a diet rich in almonds with one rich in complex carbohydrates. The almond group lost weight and maintained the weight loss at greater rates (11). Another study where participants were given 3 ounces of peanuts a day revealed that subjects tended to reduce intake from other sources during the day. They were satisfied, which led to balanced intake, promoting weight control and possibly weight loss (12).
Consuming nuts may play a role in diabetes prevention and glucose control. In a study conducted by the Harvard School of Public Health, it was suggested that nut consumption may lower the risk of Type 2 diabetes in women (13). Another recent study indicates that eating almonds may help avoid spikes in blood glucose after ingesting foods that are known to raise blood sugar levels (14). Nuts and seeds, in general, with their low glycemic index and excellent nutrient profile, are perfect as part of a diet designed to control existing diabetes.
Studies specifically analyzing nut and seed consumption and cancer risk are rather scarce. However, we do know that certain components of nuts and seeds - namely fiber and certain phytochemicals and plant sterols - help reduce the risk of certain cancers. Furthermore, we now know that it's not total fat, but the type of fat, that increases or reduces risk of breast and other cancers. Trans fats (found in processed foods and animal foods) and saturated fats (found in meats, poultry skin and full-fat dairy products) are the worst offenders. Nuts and seeds provide varying amounts of primarily unsaturated fats (75 to 80 percent), and thus are important in achieving optimal fatty acid status which, in turn, is important for a diet designed to reduce cancer risk.
In general, vegetarians and vegans tend to eat more nuts and seeds than nonvegetarians. This is not a recent or local phenomenon; cultures worldwide have used nuts as staples in plant-based cuisines for generations. In India, for example, peanuts and peanut oil are prominent parts of the vegetarian diet, and have been for thousands of years. For most modern vegetarians, nuts and seeds are not perceived as an occasional or snack food but a food consumed consistently as part of meals (15).
You've undoubtedly noticed that nuts and seeds are available in dozens if not hundreds of varieties. What to choose? Roasted? Raw? Smoked? Blanched? Spiced? Dry roasted beats oil-roasted, if these are your only choices at the grocery store. However, head to the health food store because unadulterated raw nuts and seeds are the best option. Heating and processing of nuts and seeds destroy some of the protective nutrients, but on the plus side, such processing does help to preserve nuts and seeds (processed nuts can still spoil, however). So when buying raw nuts and seeds, seek a reliable and safe source, as poorly-handled raw nuts and seeds can be a source of bacterial contamination. If you buy flavored nuts, read labels because some nuts and seeds have added gelatin, used to ensure that spices stick (16). And smoked or candied nuts can contain added fats, sugars, salt, MSG and other additives. Again, read labels and rely primarily on raw nuts and seeds. Save treats like dark-chocolate covered almonds and sesame seed candy for special occasions.
Of course, not everyone can tolerate nuts and seeds. Nut allergies are very common, and seed allergies are also becoming more prevalent, with sesame topping the list. Rates for both nut and seed allergies are rising, especially in children and young adults. Most folks who are allergic to one or more nut or seed can safely tolerate others. In severe cases, all nuts and/or seeds need to be avoided because of possible cross-contamination. For vegans who need to limit nut and seed consumption, beans and lentils are the best stand-in, with healthy amounts of leafy greens, canola oil and soy products for the missing omega 3s. Fortunately, flax seed allergy is relatively rare, and generally safe for those allergic to other nuts and seeds.
Who says the only way to enjoy nuts and seeds is by the handful? There are myriad creative ways to add nuts and seeds to your meals and snacks. And if you're not in the crunching mood, just about all nuts and seeds can be made into a "butter" or spread, or ground into a powder. Add your favorite nuts and/or seeds (or their butters) to:
Toasting nuts and seeds gives them a yummy, intense flavor. The easiest way to toast nuts is in a toaster oven, if you have one, or in an oven. Chop nuts or seeds and toast (or bake at 350 degrees) for five to 10 minutes, or until they start to brown (they'll brown even more when you remove them from the heat). Shake them around frequently or they might burn, as they tend to do quickly.
Due to their high fat content, nuts and seeds become rancid if subjected to heat, humidity or light over a certain time frame. Keep unshelled raw nuts for six months to a year in a cool, dry place. Store shelled nuts for three to four months at room temperature in an airtight container, or up to six months in the refrigerator, or a year in the freezer. Whole flax seeds can be kept at room temperature in an airtight container for one year, and ground flax seeds can be kept in an airtight, dark container in the refrigerator for 30 days, longer in the freezer.
When shopping for nuts, look for clean shells with no cracks (except pistachios, which are semi-open). Speaking of pistachios, have you noticed how scarce the red and green ones have become? Years ago, U.S. importers dyed the nuts to hide blemishes, but now most of our pistachios are grown in California, the dyes are not typically used. Another neat nut factoid: have you ever seen a cashew shell? No? It's because they contain a potent skin irritant toxin.
Sesame, sunflower, pumpkin and flax seeds, as well as almonds and peanuts and perhaps many other nuts and seeds, can be sprouted. Sprouted nuts and seeds are nutrient-rich, and sprout enthusiasts claim that the nutrients from sprouts are better absorbed than those from the native nut or seed. Certainly, the nutrient profiles of sprouts are impressive! You can do it yourself or buy sprouts at the store. Books and Web sites on the topic abound.
Seek a reliable, well-known source of your nuts and seeds. Choose a market that has a high grocery turnover and, if you buy in bulk, be sure that food safety guidelines (such as proper use of gloves, dedicated bins and cleanliness) are followed. Even the best stores and handling practices won't ensure that nuts are fresh and safe; if you detect even the slightest off-smell, return the nuts to the store. If you can't find a store near you that stocks a good variety of fresh nuts and seeds, consider an online merchant. Visit an online store that ranks high in search engine rankings and that has good customer feedback and a fair return policy. Sometimes you can buy directly from the grower!
Flax seeds are a tremendous asset to the vegetarian diet. They also have an interesting history. It is believed that flax and flax seeds were first cultivated in Babylon in 3000 B.C. Hippocrates used flax for patients with abdominal complaints, around 650 B.C. Around the eighth century, Charlemagne passed laws actually requiring people to add flax to their diets, because of how important he viewed flax to be to health (17). We are not required to eat flax seeds, but it sure is a good idea to do so! Flax seeds are among the best plant sources of omega-3 fats, plus they have lignans, an anti-carcinogen, and boron, a mineral important for bone health. Best to eat them ground, so that the nutrients are readily available (the tiny seeds are easy to swallow whole). It's a no-brainer to add ground flax seeds to mixed dishes, hot cereal and smoothies. And if you need an egg replacer for cooking, blend 1 tablespoon ground flax with 3 tablespoons water.
Hemp seeds are another super source of omega-3 fatty acids, and are showing up everywhere these days - cereals, "milk," cookies and bars, and even vegan ice cream. The seeds (and their oil) offer the greatest health benefits.
Flax and hemp oils, as expected, contain more omega-3 fats per serving than the whole seed. So why not just skip them and go directly to the extracted oil? Actually, it's not a bad idea to use high omega-3 oils in moderation. But the oil should not replace the seeds; they should both be incorporated into the diet. The whole seeds contain fiber and other important nutrients that do not end up in the oil. But the oil has concentrated amounts of protective fats. So both are important. Oils high in omega-3s oils spoil rapidly and should be kept in the refrigerator and used within a few weeks. These oils are perfect for salad dressings and smoothies but, due to low smoke points, not suitable for cooking. Healthy vegans should aim for 1/2 to 1 teaspoon of flax or hemp oil a day, depending on the rest of the diet.
If you are a vegan and concerned about your health, nuts and seeds should play a role in your daily diet. Their nutrient profiles, not to mention their flavor and versatility, go a long way in making the optimal vegan diet as nutritious and delicious as it can be.
(1-17) References for this article are available from NAVS at firstname.lastname@example.org or P.O. Box 72, Dolgeville, NY 13329.
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