Nutrition In A Nutshell
Cracking the Nutritional Content of Nuts
Illustration © D. Yael Bernhard
Autumn is upon us. Here in the Northeast, the leaves are falling fast. The hickory tree drops its nuts on the metal roof of my woodshed, each producing a flat thud, while green felt-covered walnut shells fall lazily on the grass, coming to a stop like forgotten tennis balls. A squirrel sits on a large rock, diligently chewing one apart, leaving a flaky brown mess. Chipmunks go for the smaller acorns produced by a nearby stand of oaks, running back and forth with their bounty, to be buried under the old stone wall that once divided the forest behind my house into mountainside pasture.
With their hard outer shells, nuts are able to endure the harsh conditions of winter. Nuts are a type of fruit, but I think of them as tree eggs, containing all the nourishment needed to support a new life. Surrounded by nutrient-dense fat and protein, the single seed inside has a good chance of surviving until it can sprout into a seedling. The flesh of nuts must also appeal to animals, for nut-bearing trees depend on them to pick them up and bury them in the earth. Rodents frequently lose track of these stashes, giving the tree’s offspring a fighting chance to grow into a new tree.
Crack open the contents of a nut, and you might be surprised by what you find. Nature’s little nuggets provide a well-balanced blend of protein, fat, and fiber, all wrapped up together in a non-perishable shell. With their high fat content, nuts help animals survive the winter. For us, they’re a satisfying snack, easy to eat on the go, better than any energy bar – and no plastic wrapper. Nuts contain beneficial fats and plant sterols that provide the raw ingredients for hormones and healthy cholesterol.1 They have just enough carbohydrates to give you energy, with sufficient fiber to mete it out slowly, reducing hunger and lowering the need for insulin. By lowering insulin, healthy fats facilitate weight loss rather than cause weight gain. (See my article “It’s All About Insulin” to learn how this works.)
But there’s more to these crunchy little gifts of the forest than their macronutrients. Different kinds of nuts and seeds have their own special secrets tucked away in their shells. Here are a few common examples:
Walnuts have so many nutrients, they’re like a whole meal. Seven walnuts contain 2g of fiber, 4.3g of protein, 3.8g of carbohydrates, and 18.5g of total lipids, including both polyunsaturated and monounsaturated fats. In terms of minerals, walnuts are highest among nuts in magnesium (45mg), phosphorus (90mg), and potassium (125mg), with moderate amounts of calcium, iron, manganese, selenium, copper, and zinc. Folate and other B vitamins, vitamin C, beta carotene, vitamin K, and vitamin E are also found in modest amounts. And there’s an added plus: walnuts contain alpha-linolenic acid, an omega-3 essential fatty acid that most nuts do not have. This beneficial EFA also raises the comparative acidity of walnuts, however, so it’s still not wise to eat too many. The acidity of walnuts may be offset by eating them with alkaline foods, such as leafy green vegetables, avocados, beets, quinoa, celery, and lentils – to name just a few.
Almonds are rich in L-arginine, an amino acid that acts as a precursor to nitric oxide, a signaling molecule that acts as a vasodilator and boosts the activity of antioxidants. A quarter-cup of these delicious nuts contains 4g of fiber, 7g of protein, and 6g of carbs; as well as potassium (260mg), magnesium (260mg), calcium (89mg), phosphorus, and small amounts of zinc and molybdenum. A one-ounce serving contains 50% of the RDA of vitamin E, a nutrient that is essential for cardiovascular health and cellular reproduction. Vitamin E is controversial in supplement form, so it’s best to gather this nutrient from food.
Pistachio nuts also sport a good amount of protein, with 6g in a 1 ounce serving (about 50 kernels), 3g of fiber, and 8g of carbs. Pistachios are said to contain more melatonin than the average sleep supplement, making them a good evening snack. Try eating 1/4 cup with kefir, which contains sleep-inducing tryptophan, 2-3 hours before bedtime.
Macadamia nuts are high in a rare, beneficial fat known as omega-7. Also known as palmitoleic acid, this essential fat is known to improve insulin sensitivity and help shed excess body fat – precisely the opposite of the what we were taught back in the 20th century. Macadamia nuts are also notoriously low in inflammatory omega-6 fats, and as high in monounsaturated fat as olive oil, which is known to improve cholesterol and support cardiovascular health. These crunchy little balls are also high in calories, however. Ten nuts are all you need.
Brazil nuts are exceptionally high in selenium, a mineral that is critical for immunity and for activating thyroid hormone. Just one or two nuts per day is sufficient. Excess selenium may be toxic, so please do not exceed this amount; and do not eat Brazil nuts together with vitamins that contain selenium.
Hazelnuts are rich in manganese, copper, folate, and vitamin E, and provide protein and fiber similar to the other nuts noted here. They have a unique flavor which may be used as a spice or an extract. Hazelnuts are a good choice for diversifying your diet.
Pecans are noted for their versatility – delicious eaten alone or used in a variety of recipes and cuisines. They are grown in such diverse places as Mexico, Peru, South Africa, Israel, and Australia. Like other nuts, pecans are rich in friendly fats, as well as antioxidants and moderate amounts of protein, fiber, and carbohydrates.
Cashews are technically seeds, coming from a fruit with an outer shell that contains urushiol, the same toxin found in poison ivy leaves. Cashews must be carefully processed to remove this toxin. Sensitive individuals may break out in a skin rash from eating cashews. Cashews are higher in carbohydrates than other nuts. They offer a modest amount of copper, magnesium, zinc, and vitamin B6.
For all these reasons and more, whole nuts are the snack that I take with me on the run, whether doing errands, a day trip, or traveling. I love sliced apples with almond butter, chopped walnuts in yogurt, and pistachio nuts with berries and kefir.
The low levels of carbohydrates in nuts are an advantage both for the life of the seeds they contain, and for us – for nutrient-dense fat and protein are the gold in these nuggets. But what about fruit, you might wonder? The seeds of apples, peaches, grapes, and plums are surrounded by sweet, juicy flesh that’s high in fructose. Isn’t that just as nourishing for starting a new life?
Not exactly. These fruits are meant to be consumed by animals, who then carry the seed inside them, to pass through their digestive tract and land in the earth far from the parent tree. The tree benefits by getting a free ride for its seeds. The animals benefit by rapidly gaining weight that will carry them through the winter – for fat storage is the very purpose of fructose (see my article “Fructose: Friend or Foe?” for more on this subject.) The fruit is there to aid in seed dispersal, and for the benefit of the tree’s symbionts, the animals of the forest – not the seed itself. Fruit and grain seeds are more plentiful than nuts because many do not survive. Nature invests more in feeding the embryos inside nuts, and favors protein and fat over carbohydrates. The same is true of eggs, which contain virtually no carbohydrates.
What about other forms of nut-based foods?
Nut and seed butters are also healthy foods, provided they are not consumed in excess. The more processed a food, the more quickly its oils become rancid, and the lower the fiber content. In their whole, original form, the nutrients in nuts are delivered within a complex matrix of cofactors that are not the same when dismantled. Almond flour, for example, does not confer the same nutritional value as whole almonds – especially after traveling a long distance and sitting on a shelf in a plastic bag for a period of months. It’s okay to eat nut butters and nut flours – just be sure to also eat these foods in their original form.
Nut oils such as almond and walnut oil are healthy, but tend to be expensive and tricky to cook with. Your ideal cooking oils are fruit oils: coconut, olive, and avocado, as well as animal-based fats such as grass-fed butter, ghee, beef tallow, and duck or goose fat. Avoid vegetable and seed oils (see my article “Know Your Oils” for more on this subject.)
Nut beverages (“milks”) are fairly worthless, completely lacking in fiber, and tend to have added sugars, harmful thickeners such as carageenan, and other unwanted ingredients.
The Problem With Peanuts
By now you might be wondering why I haven’t mentioned peanuts. Like many of my peers, I grew up with peanut butter and jelly sandwiches. They were always the same: Skippy peanut butter and Welch’s grape jelly on Wonderbread. Back in the 60s and 70s, there weren’t too many other choices. Looking back, I groan at the damage these junk foods did to my developing metabolism, which began to go south by the time I was fifteen. Peanuts are not nuts – they are legumes, though they are thought of and used as nuts in our culture. I have no problem with peanuts in principle, but in practical terms they pose a number of health issues. Many brands of peanut butter contain hydrogenated oil, added to maintain a creamy texture. These chemically-produced “trans fats” are now known to cause heart disease and cancer. No one knew better back then, least of all my young mother or hard-working father. Today trans fats are banned in the U.S., yet food manufacturers have found loopholes to continue using them. Check labels carefully, both front and back.
Peanuts are a popular ingredient in many highly-processed foods that are loaded with chemicals and poorly packaged, shipped, and stored. Their woody fiber is difficult to digest, and their oil contains inflammatory omega-6 fats. Peanuts have been over-cultivated and hybridized for centuries, especially since colonial times, and have evolved into a weak crop that is vulnerable to a particular fungus known as aflatoxin. Aflatoxin is one of the most potent naturally-occurring toxins. It’s a known carcinogen, particularly of the liver, and may also suppress the immune system.2 Aflatoxin has been linked to infertility, birth defects, and stunted growth in children.3 These nasty mycotoxins are also found in other staple plant foods such as corn, wheat, and rice; and grain-fed animals may become contaminated through their food. But peanuts lead the way with the highest amounts of aflatoxins. Levels vary widely according to climate (humidity) of where they’re grown, harvesting techniques, and storage. In Europe, aflatoxins are strictly monitored and kept at very low, theoretically safe levels. Here in the United States, where the profits of food manufacturers are protected more than the health of consumers, peanuts and peanut products may contain up to ten times as much aflatoxins.
“The use of peanut oil in human food is frequently overlooked as a source of aflatoxin exposure.”4
Peanut oil is relatively inexpensive, and is often used to roast other nuts. While roasting and salting nuts may make them more appealing and in some ways more digestible, using peanut oil is not a good way to do it. Peanut oil becomes rancid when exposed to high or prolonged heat. Avoid mixed nuts that are roasted or coated in peanut oil. There are better ways to make salt stick: try tossing your nuts with olive oil and salting them yourself. While you’re at it, you can use salt that is not bleached with chemicals, contaminated with nanoplastics from the ocean, and devoid of minerals.
And then there are lectins, a protein in many nuts, seeds, and other plant-based foods such as beans and grains. Lectins are known as “anti-nutrients” – compounds that bind to carbohydrates as well as the cells in intestinal walls, interfering with nutrient absorption and sometimes causing digestive upset, nausea, vomiting or diarrhea. Once again, peanuts lead the way with the highest levels of lectins. Lectins may be reduced or nearly eliminated by soaking and cooking at high temperatures – which is why it’s best to soak your beans before cooking them, and to cook them in liquid. But how often do you soak or cook your peanuts? Peanut sauces may be slightly better, but are generally not cooked at high enough temperatures. Roasting helps to decrease lectins, but alas, it also causes the above-mentioned problems.
Peanuts do contain protein, fat, and some folate – but these nutrients are readily available elsewhere. Personally, I’d rather skip the peanuts and pursue the many other options available to me.
Phytates are another anti-nutrient found in many nuts and seeds. Like lectins, phytates interfere with mineral absorption. This is of particular concern for vegans and vegetarians who rely heavily on plant-based foods for zinc. Zinc is crucial for immunity and healing, for balancing copper, and many other biochemical functions. Your best sources of zinc are meat, fish, oysters, pasture-raised dairy, and eggs – none of which contain phytates.
Among nuts, cashews have the highest levels of phytates, with almonds in second place. The phytates in almonds are in the skins, which may be easily removed by soaking them for several hours in water. These “blanched” nuts may then be dried in a dehydrator or a low oven. My dehydrator is not much bigger than a toaster oven. While soaking and drying nuts may seem daunting for someone who is new to it, for me it’s an easy addition to other kitchen activities. I like to pinch the skins off almonds while watching a good movie, or even as a social activity: pinching off the skins and snacking on the wet, milky nuts is fun and makes for good conversation – rather like shelling peas, peeling apples, or shucking corn.
And there’s another reward to soaking nuts: much less flatulence after eating them.
Small amounts of phytates and lectins are actually thought to be beneficial – for after all, plants produce them for their own protection against oxidative stress. We, too, may benefit from the antioxidant effect of anti-nutrients – but is it worth it for the loss of minerals and other negative effects? Antioxidants may be found in literally hundreds, if not thousands, of other foods.
Getting the Most Out of Nuts
A diet of diverse plant- and animal-based foods is the best way to reduce phytates and lectins as well as increase the number and type of antioxidants in your diet. Eating the same foods over and over again, like inbreeding within the same gene pool, doubles and triples the bad components of what you eat. Our prehistoric hunting and foraging ancestors didn’t do this, and our biochemical hard-wiring hasn’t changed much since then. Vary your nuts and seeds, and you will avail yourself of a plethora of beneficial antioxidants while preventing a build-up of anti-nutrients.
Nuts preserve fairly well in a fridge, freezer, or even a closed container in a cool basement – so it’s worth shopping around and buying larger quantities. Make your own mixes. Experiment with roasting and salting your own nuts. Take them with you as a convenient snack. To reduce insulin spikes, eat the fiber, fat, and protein in a handful of nuts before a high-carb piece of fruit. Place a walnut on every bite of a banana. Add nuts to the topping of fruit crisp to bring more nutritional value into your dessert. Try making a gluten-free pie crust with ground nuts instead of flour. Experiment with nut butters on sliced fruit or vegetables; or try nuts as a nutritious topping for hearty soups.
When it comes to food, it’s good to be fickle. Here in North America, we’re blessed with access to an extraordinary array of foods. Nuts are a convenient, portable, versatile, nutrient-rich, energy-dense food. We would do well to learn from the animals of the forest, and treasure these gifts of the earth.
To your good health –
Yael Bernhard
Certified Integrative Health & Nutrition Coach
Yael Bernhard is a writer, illustrator, book designer and fine art painter with a lifelong passion for nutrition and herbal medicine. She was certified by Duke University as an Integrative Health Coach in 2021 and by Cornell University in Nutrition & Healthy Living in 2022. For information about private health coaching or nutrition programs for schools, please respond directly to this newsletter, or email dyaelbernhard@protonmail.com. Visit her online gallery of illustration, fine art, and children’s books here.
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https://journalmedicals.com/index.php/AJOAIMS/article/view/90
https://link.springer.com/article/10.1007/s12403-022-00499-9
https://www.wageningenacademic.com/doi/abs/10.3920/WMJ2017.2279