If someone were to ask me which nut offers the greatest “bang for the nutritional buck” (and bang for the actual buck!) I would say, hands down, it’s walnuts. Not many people realize this, but walnuts have 30% less net carbs (only 1.9g net carbs per 1 oz serving) and more protein per ounce than almonds, whose flour is the primary ingredient in many low-carb recipes. I’ve personally switched from using almond flour in my recipes to using walnut flour and haven’t looked back! And to top it all off, walnuts contain the following 11 essential nutrients for anyone on a keto diet:
1. Omega-3’s
Walnuts are the only nut to contain a significant amount of the essential polyunsaturated fatty acid omega-3 fat known as alpha-linolenic acid (ALA); each ounce of walnuts contains 2.5 grams of plant-based omega-3 alpha-linolenic acid (ALA).
Health Benefits: There is strong evidence demonstrating alpha-linolenic acid’s beneficial role in both the prevention and management of cardiovascular disease.
2. Polyphenols
Walnuts are one of the most important sources of a class of plant compounds known as polyphenols, or phenols, containing up to 2500 mg/100 g, and are the richest plant source of the polyphenol ellagitannin (∼1600 mg/100 g). Approximately 90% of the phenols in walnuts are found in the skin, which include another category of phenols known as flavonoids.
Health Benefits: Ellagitannins are metabolized into compounds with anti-inflammatory, antioxidant, and prebiotic effects.
3. Vitamin E
Walnuts provide an unusually high level of Vitamin E in the form of gamma-tocopherol, supplying 21 mg/100 g. Most of the Vitamin E present in other nuts and seeds is the more common form of Vitamin E called alpha-tocopherol.
Health Benefits: Evidence supports this special form of Vitamin E’s unique role as a potent antioxidant and anti-inflammatory compound. Gamma-tocopherol is, therefore, considered to be more heart-protective than its “close relative”, alpha-tocopherol.
4. Melatonin
Walnuts are one of the main food sources of bioavailable melatonin, referred to as phytomelatonin, with an average content of 0.35 mg/100 g.
Health Benefits: Research on phytomelatonin supports its potential health benefit as an antioxidant for a wide range of diseases and disorders caused by oxidative stress and aging.
5. Manganese
Walnuts are an excellent source of manganese, providing ~44% of the RDI for adults in a 1-oz serving.
Health Benefits: This essential trace mineral is required for the formation and function of a powerful antioxidant enzyme known as superoxide dismutase (SOD) which plays an essential anti-inflammatory role in our body. Manganese is largely concentrated in the pancreas, which may help the proper secretion of insulin and help stabilize blood sugar.
6. Plant Sterols
Walnuts are among the foods with the highest concentration of plant sterols, or phytosterols, containing 113 mg/100 g. Phytosterols play a structural role in plant membranes similar to that of cholesterol in animal membranes.
Health Benefits: Phytosterols are considered to be one of the compounds contributing to the LDL-cholesterol lowering effect of walnuts.
7. Magnesium
Walnuts are a good source of magnesium, providing 44 mg in a 1 oz serving, or ~11% of the Recommended Daily Intake (RDI) for women, which is 320-360 mg/day.
Health Benefits: This nutritional powerhouse is one of the most abundant minerals in the body, involved in a number of reactions including protein synthesis, energy production, blood sugar control, and blood pressure regulation. Magnesium also helps to regulate nerve function (calming the mind, promoting relaxation and improving sleep), enables optimal digestion, and promotes healthy muscle function and a normal heart rhythm.
8. Copper
Walnuts are an excellent source of copper, providing ~53% of the recommended daily requirement (RDI) for adults in a 1-oz serving.
Health Benefits: Copper helps the body form red blood cells and aids in iron absorption. It also helps maintain the health of blood vessels, bones, and functions of the nervous and immune systems.
9. Amino Acids
The predominant amino acids in walnuts are the essential amino acid L-Arginine and the nonessential amino acid Glutamic Acid.
Health Benefits: L-Arginine is converted in the body to nitric oxide which boosts blood flow throughout the body, decreases the narrowing of arteries and other blood vessels, and prevents the fatty build-up on the artery walls. Glutamic acid is the most common plant-based dietary amino acid and is another key compound linked to the blood pressure-lowering effect of vegetable proteins.
10. Molybdenum
A 1 oz serving of walnuts provides ~20% of the RDI for the trace mineral molybdenum.
Health Benefits: Molybdenum is essential for the activity of several enzymes, including an enzyme that breaks down nitrate and is critical to nitric oxide production.
11. Biotin
A 1 oz serving of walnuts provides ~19% of the RDI for biotin.
Health Benefits: As a B-Complex vitamin, biotin is an essential component of enzymes involved in the the metabolism of carbohydrates, fats, and proteins, helping to convert food into energy. Biotin can also help maintain healthy hair, skin, and nails.
Takeaway Message
Among all nuts, walnuts contain the highest level of the essential omega-3 fatty acid alpha-linoleic-acid (ALA), providing benefits similar to the omega-3’s in fatty fish. These fatty acids in walnuts promote heart and blood pressure health, support brain health and mood, and play a role in both weight and blood sugar management. Compared with all other nuts, walnuts also contain the greatest concentration of the antioxidants known as polyphenols and gamma-tocopherol. Walnuts are also one of the best sources of plant sterols and are rich in the trace minerals manganese, copper, and molybdenum. Each of these nutrients, in addition to several others, such as fiber, phytomelatonin, and L-arginine, have unique properties that positively impact health and, working in unison, offer an even greater benefit for both preventing and managing disease.
