There are no shortage of ‘diets’ out there claiming to treat or improve autoimmune disease. You may have come across AIP (Autoimmune Paleo), low-nightshade, gluten-free, sugar-free, vegan, and the carnivore diet, just to name a few. In this two-part blog, I aim to provide research around nutrition and the immune system and put to rest the notion that you must follow a strict ‘diet’ if you have an autoimmune disease. Instead, we need to consume a variety of whole foods, especially plants, and limit non-food additives/preservatives that are commonly found in packaged foods.
I am going to start by highlighting the importance of a few key nutrients that you may be low in if you are currently eating the SAD, or Standard American Diet. According to the most recent US Dietary Guidelines, there are 7 nutrients that most American’s aren’t getting enough of: calcium, potassium, fiber, magnesium, vitamin A, vitamin C and Vitamin E.(1) Several of these are critical for our immune system. Below, I outline a few reasons why each is important for immune function and include some food options to get more of each.
Vitamin A: Vitamin A is critical for immune tolerance. Researchers from Emory University found that “Dendritic cells, the microbe-sensing alarms of the immune system, can send out a "red alert" to stimulate immunity, or a "calm down" message that tones down excessive immunity that might damage the host. The "calm down" message makes use of vitamin A, providing an explanation for the link between vitamin A deficiency and autoimmune diseases.” (2)
Food sources: (3) liver, meat, dairy and fish contain preformed vitamin A. Sweet potato, pumpkin, spinach, carrots, cantaloupe and sweet peppers contain a precursor to vitamin A
Vitamin C: This might be the most ‘famous’ immune supportive nutrient. Vitamin C is a potent antioxidant and required for many reactions in our body. Vitamin C supports both the innate and adaptive immune system (4). When we don’t have adequate vitamin C in our tissues we can develop impaired immunity and higher levels of inflammation.
Food sources: (5) raw sweet peppers, oranges, grapefruit, kiwi, broccoli, strawberries, and Brussels sprouts
Vitamin E: Vitamin E is well known for its antioxidant activity but lesser known for its role in the immune system. Vitamin E is highly concentrated inside of white blood cells and plays a role in stimulating our defense mechanisms. A literature review published in Reviews in Clinical Medicine found “A decrease in the serum levels of vitamin E in almost all autoimmune diseases. Furthermore, there is evidence regarding the possible therapeutic value of vitamin E in the management of autoimmune diseases.” (6) A clinical trial from 1978 found that providing vitamin E to patients with varying autoimmune skin conditions provided benefit.(7)
Food sources: (8) wheat germ, sunflower seeds, almonds, sunflower oil, safflower oil, hazelnuts, peanut butter
Fiber: I don’t have any interesting research studies to share on fiber and the immune system. I bring up this important nutrient because fiber is a major way that we feed our beneficial flora otherwise known as the microbiome. I explained the importance of our microbiome in my article Holistic Autoimmunity Series: Gut Health (link to GI and autoimmune article) so I will be brief. Our microbiome helps to train our immune system and likely play an integral role in autoimmune disease. So eat fiber to feed your microbiome friends!
Food sources: (9) beans, chia seeds, flaxseeds, barley, green peas, raspberries, pear
Omega-3’s: A nutrient that I believe is missing from this list is omega-3 fatty acids. The most important fatty acids for immune health are EPA and DHA which are found in certain fish. Omega-3’s reduces tumor necrosis factor-α and interleukin-6 production which are two inflammatory signals in the body (10). Omega-3’s are also important because autoimmune disease increases the risk of cardiovascular disease via increased inflammation and omega-3’s can help reduce that risk. “Many of the placebo-controlled trials of fish oil in chronic inflammatory diseases reveal significant benefit, including decreased disease activity and a lowered use of anti-inflammatory drugs.” (11).
Food sources: There is an acronym that helps me remember these fish; SMASH (Salmon, Mackerel, Anchovies, Sardines, and Herring). It’s ideal to consume a fish high in omega-3’s twice per week. Food is best, but if you can’t get these in twice per week I recommend using a fish oil supplement.
Vitamin D: I would be remiss if I didn’t at least touch on vitamin D. We don’t get much from food BUT it’s name is vitamin D so I will include a brief note about it here. Vitamin D truly acts as more of a hormone in the body. We make vitamin D from cholesterol when our skin is exposed to sunlight. It’s challenging to make enough in Minnesota since we are so far from the equator where the sun’s rays are the most direct. A literature review conducted in 2016 found “an inverse association between vitamin D and the development of several autoimmune diseases, such as SLE, thyrotoxicosis, type 1 DM, MS, iridocyclitis, Crohn's disease, ulcerative colitis, psoriasis vulgaris, seropositive RA, polymyalgia rheumatica.” (12). What this means is that when your vitamin D levels are in an optimal range you are less likely to develop an autoimmune disease. I advocate for testing vitamin D levels in patients and typically aiming for a blood level around 60 ng/mL.
Food sources: We can get some vitamin D from mushrooms, pasture-raised egg yolks and liver, but this is usually not enough to meet biological needs.
- Missing Nutrients in Your Food
- Vitamin A Signals Offer Clues To Treating Autoimmunity
- Vitamin A Fact Sheet for Health Professionals
- Vitamin C and Immune Function
- Vitamin C Fact Sheet for Health Professionals
- Vitamin E and Autoimmune Diseases: A Narrative Review
- Is vitamin E involved in the autoimmune mechanism?
- Vitamin E Fact Sheet for Health Professionals
- Mayo Clinic Healthy Lifestyle: Chart of high-fiber foods
- Inhibition of tumour necrosis factor-α and interleukin 6 production by mononuclear cells following dietary fish-oil supplementation in healthy men and response to antioxidant co-supplementation
- Omega-3 fatty acids in inflammation and autoimmune diseases
- Emerging role of vitamin D in autoimmune diseases: An update on evidence and therapeutic implications
Additional reference not specifically cited above: Diet, Gut Microbiota, and Vitamins D + A in Multiple Sclerosis