Why Nuts and Seeds Are (Usually) Allowed on Anti-Inflammatory Diets

If you look at look up nutrition facts for nuts or seeds, you'll notice that, with few exceptions, these little energy-boosters contain much more omega-6 fatty acids than omega-3 fatty acids. However, most modern diets already contain far too much of the omega-6s and not enough of the omega-3s, an imbalance that some experts believe is linked to the prevalence of the wide range of inflammatory conditions in the modern world. So the question is, why are nuts and seeds then usually allowed on anti-inflammatory diets, such as The Omega Diet devised by Dr. Artemis Simopoulos, one of the world's most renowned authorities on essential fatty acids, or the eating plan presented in Dr. Jessica Black's hugely popular book The Anti-Inflammation Diet?

The answer is actually fairly simple: nuts and seeds are not only made of polyunsaturated fats, such as omega-6s and omega-3s, but most of them also contain tons of monounsaturated fats, protein, fiber, vitamin B6, vitamin E, minerals and phytochemicals. And, many of these nutrients have anti-inflammatory effects. So, the point is, even if the omega-6-to-3 ratio does play a role in inflammation (some experts suggest it doesn't – more on that here), it is hardly the only thing that defines whether a specific food has pro-inflammatory or anti-inflammatory properties.

In this article, we take a look at some anti-inflammatory nutrients found in nuts and seeds, plus provide an overview of some of the studies that have demonstrated the anti-inflammatory properties of nuts.

Nuts and Seeds Contain a Variety of Anti-Inflammatory Nutrients

Monounsaturated Fats

Even though most nuts and seeds have a fairly high fat content, not all of them are loaded with polyunsaturated fatty acids (PUFAs) such as omega-6s or omega-3s. In fact, most common nuts – including almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, peanuts, pecans and pistachios – contain more monounsaturated fatty acids (MUFAs), particularly oleic acid, than polyunsaturated fatty acids. Seeds tend to have higher PUFA to MUFA ratios than nuts, but many of them still contain significant amounts of MUFAs. While more research is still needed, there is some evidence suggesting that oleic acid can reduce biomarkers of inflammation.

Walnuts are a notable exception in the nut world in that they actually contain more polyunsaturated fats than monounsaturated fats. However, compared with other nuts, the omega-6 to omega-3 ratio of walnuts is very low (around 4 to 1), which is why this popular tree nut is often considered one of the best plant-based sources of omega-3s.

Vitamin E

Most nuts and seeds are loaded with vitamin E, either in the form of alpha-tocopherol or gamma-tocopherol. Alpha-tocopherol, which is abundant in almonds, hazelnuts, pine nuts and sunflower seeds, has been shown to exert anti-inflammatory effects through multiple mechanisms, including decreasing levels of CRP and pro-inflammatory cytokines and inhibiting the activity of protein kinase C and other enzymes, such as cyclooxygenase-2. Also gamma-tocopherol – a type of vitamin E found in high amounts in Brazil nuts, cashews, pecans, pine nuts, pistachios, walnuts, flaxseed, pumpkin seeds, poppy seeds and sesame seeds – has been shown to exert anti-inflammatory activities in some laboratory and animal studies.

Other Nutrients

There are of course also many other nutrients that may contribute to the anti-inflammatory properties of nuts and seeds. A study published in the journal Circulation, for example, found that people with lower levels of vitamin B6 – found in high amounts in most nuts and seeds – had higher levels of C-Reactive Protein (CRP) which is an inflammatory marker. And the protein and fiber in nuts and seeds promote satiety, which in turn may help combat obesity, a common risk factor for chronic inflammation. Just keep in mind that nuts and seeds are also pretty high in calories, so only eat them in moderation to keep your overall calorie intake in check.

Anti-Inflammatory Properties of Nuts Demonstrated in Studies

The anti-inflammatory properties of nuts have also been demonstrated in studies. In a cross-sectional analysis involving about 6000 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), consumption of nuts and seeds was inversely associated with levels of inflammatory markers, C-reactive protein (CRP), interleukin-6 and fibrinogen. Another study with nearly 1000 diabetic women from the prospective Nurses' Health Study found a direct association between nut consumption and increased plasma levels of adiponectin, an adipose tissue-secreted cytokine with anti-inflammatory properties.

Also many studies investigating the effects of a specific nut on inflammation have shown promising results. For example, one study found that ingestion of Brazil nuts was associated with a long-term decrease in inflammatory markers in healthy volunteers, while another study associated hazelnut-enriched diets with lower levels of CRP.

Despite Being Generally Anti-Inflammatory, Nuts Trigger Inflammatory Responses in Some People

In some individuals, inflammatory conditions may be caused or aggravated by allergies or intolerances to specific foods, including nuts and seeds. In fact, both peanut and tree nut allergies are among the top 10 most common food allergies in the United States. If you suffer from a true nut or seed allergy, you are probably already aware of it as the symptoms are typically severe and easy to identify; however, if you are only mildly intolerant to specific nuts or seeds, you may not be aware of your condition. A qualified health care professional, or in many cases a certified nutritionist, can help you identify food allergies and intolerances.

References:
E. Ros (2010). Health Benefits of Nut Consumption. Nutrients, Jul; 2(7): 652-682.
E. Ryan et al (2006). Fatty acid profile, tocopherol, squalene and phytosterol content of brazil, pecan, pine, pistachio and cashew nuts. International Journal of Food Sciences and Nutrition Volume 57, Issue 3-4.
A. Basu, S. Deveraj and I. Jialal (2006). Dietary Factors That Promote or Retard Inflammation. Arteriosclerosis, Thrombosis, and Vascular Biology, 26: 995-1001.
R. Thomas and S. Gebhardt. Nuts and seeds as sources of alpha and gamma tocopherols. USDA-ARS Nutrient Data Laboratory, Beltsville, MD.
P. Calder et al (2009). Inflammatory disease processes and interactions with nutrition. British Journal of Nutrition, 101 Suppl 1: S1-45.
U. Singh, S. Devaraj and I. Jialal (2005). Vitamin E, oxidative stress, and inflammation. Annual Review of Nutrition, 25: 151-74.
Q. Jiang and B. Ames (2003). Gamma-tocopherol, but not alpha-tocopherol, decreases proinflammatory eicosanoids and inflammation damage in rats. Faseb J, 17(8): 816-22.
Q. Jiang et al (2000). Gamma-tocopherol and its major metabolite, in contrast to alpha-tocopherol, inhibit cyclooxygenase activity in macrophages and epithelial cells. Proc Natl Acad Sci U S A 2000; 97(21): 11494-9.
F. Simonetta (2001). Low Circulating Vitamin B6 Is Associated With Elevation of the Inflammation Marker C-Reactive Protein Independently of Plasma Homocysteine Levels. Circulation, 103: 2788-2791.
R. Jiang et al (2006). Nut and seed consumption and inflammatory markers in the Multi-Ethnic Study of Atherosclerosis. Am. J. Epidemiol, 163:222-231.
C. Mantzoros et al (2006). Adherence to the Mediterranean dietary pattern is positively associated with plasma adiponectin concentrations in diabetic women. The American Journal of Clinical Nutrition, 84:328-335.
E. Colpo et al (2014). Brazilian nut consumption by healthy volunteers improves inflammatory parameters. Nutrition, 30(4):459-65.
A. Orem et al (2013). Hazelnut-enriched diet improves cardiovascular risk biomarkers beyond a lipid-lowering effect in hypercholesterolemic subjects. J Clin Lipidol., 7(2):123-31.