Browse the evidence

Vitamin D supplementation reduces the incidence of acute respiratory tract infections, with the effect being more significant in patients with severe vitamin D deficiency (<10 ng/mL).

Taking vitamin D supplements can help reduce the risk of getting acute respiratory infections. This benefit is strongest if you currently have severe vitamin D deficiency. If your levels are normal, the benefit may be smaller.

Direct supplementation with Urolithin A (UA) improves skeletal muscle mitochondrial function and health span in elderly humans, bypassing the need for gut microbiome conversion of dietary precursors.

If you are over 60 and interested in supporting muscle health and mitochondrial function, direct Urolithin A supplementation is a viable option, especially if you do not naturally produce it from your diet. The first human trials show it is safe and improves muscle biomarkers. You do not need to rely on eating pomegranates or berries, as your gut may no longer convert them effectively.

Daily consumption of 20g of extra-virgin olive oil (EVOO) containing at least 5mg of hydroxytyrosol (HT) and its derivatives provides cardioprotective benefits, including protection of LDL from oxidative damage, maintenance of normal blood pressure, and anti-inflammatory effects.

To get the heart-protective benefits described, you need to eat about 1.5 tablespoons (20g) of high-quality Extra-Virgin Olive Oil every day. It is not enough to just eat 'olive oil'; it must be Extra-Virgin and contain at least 5mg of hydroxytyrosol and its derivatives. This fits into a Mediterranean diet pattern rich in vegetables and fruits. If you are at high risk for heart disease, this specific intake has been shown to significantly reduce major cardiovascular events compared to a low-fat diet.

Fermented dairy products can alleviate lactose intolerance symptoms by degrading lactose through the action of lactase produced by lactic acid bacteria.

If you are lactose intolerant, try eating yogurt or kefir. The bacteria in these foods break down most of the lactose, making them easier to digest than regular milk. Start with small amounts to see how your body reacts.

Consumption of animal-source foods (ASF) by children aged 6-23 months in low- and middle-income countries significantly reduces stunting and improves cognitive development compared to plant-based or starch-heavy diets.

If you live in a region where stunting is common and diets rely heavily on starches, introducing small amounts of animal-source foods (like eggs, milk, or fish) to young children is one of the most effective ways to prevent stunting and support brain development. This is not about overconsumption, but about filling critical nutrient gaps that plant-based diets often miss.

Fish oil and Eicosapentaenoic Acid (EPA) supplementation (2.0-2.2 g/day EPA and 1.5 g/day DHA) can help preserve skeletal muscle and reduce intramuscular adipose tissue in cancer patients, particularly those with advanced lung or pancreatic cancer.

Cancer patients, especially those with lung or pancreatic cancer, may benefit from fish oil supplements providing 2-2.2g of EPA and 1.5g of DHA daily. This can help preserve muscle mass and reduce harmful intramuscular fat during chemotherapy.

Polyphenol-rich functional foods (green tea, yerba mate, coffee) improve insulin sensitivity, reduce oxidative stress, and lower fasting glucose.

Incorporate polyphenol-rich beverages like green tea and yerba mate into your daily routine. Clinical trials show these can significantly lower fasting glucose and improve antioxidant capacity.

Nutritional ketosis, induced by carbohydrate restriction or caloric restriction, reduces systemic inflammation and ASCVD risk markers primarily through the ketone body beta-hydroxybutyrate (BHB) inhibiting the NLRP3 inflammasome.

If you have insulin resistance, reducing refined carbohydrates can trigger ketone production. This helps lower inflammation by blocking specific immune sensors (NLRP3), offering cardiovascular protection beyond just weight loss.

Vitamin D3 supplementation significantly reduces cancer mortality by 16%, whereas Vitamin D2 does not show this benefit.

If you take Vitamin D for cancer prevention, ensure you are taking Vitamin D3, not D2. This review found a 16% reduction in cancer death risk with D3, but no such benefit with D2. D3 is also more effective at raising blood levels of Vitamin D.

Systematic vitamin D food fortification is an effective and cost-effective public health strategy to improve population-level vitamin D status and reduce deficiency, overcoming the limitations of individual supplementation and sunlight exposure.

If you live in a region with limited sun or eat few fatty fish, look for vitamin D-fortified foods like milk, margarine, or orange juice. This is a safe, passive way to maintain healthy vitamin D levels without needing to remember daily supplements. Check local guidelines for what foods are typically fortified in your country.

CoQ10 supplementation (100-300 mg/day) improves mitochondrial function and reduces cardiovascular mortality in elderly populations with low baseline CoQ10 levels, particularly when combined with selenium.

If you are elderly and have low CoQ10 levels, supplementation with 200mg CoQ10 daily, potentially combined with 200mcg of selenium, may significantly reduce your risk of cardiovascular death over the long term. Consult a doctor to check your baseline levels before starting.

CoQ10 supplementation (100-300 mg/day) reduces inflammatory markers (TNF-α, IL-6) in patients with metabolic diseases, rheumatoid arthritis, and other inflammatory conditions.

If you have chronic inflammation, metabolic syndrome, or rheumatoid arthritis, taking 60-500mg of CoQ10 daily may help lower inflammatory markers like TNF-α and IL-6. This is particularly relevant if you have low baseline CoQ10 levels.

Vitamin E (96-week course) improves NASH resolution in non-diabetic patients, but its use is limited by potential risks of hemorrhagic stroke and prostate cancer.

If you have NASH and are not diabetic, ask your doctor about Vitamin E. A 96-week course can significantly improve liver health (43% resolution vs 19% placebo), but you must weigh this against potential risks like prostate cancer or stroke.

Daily supplementation with vitamin D (400-800 IU) combined with calcium (1000-1200 mg) reduces the risk of hip fracture by 16% in older adults, whereas vitamin D alone provides no significant fracture protection.

If you are an older adult looking to prevent hip fractures, taking Vitamin D alone is likely ineffective. You should take a daily combination of Vitamin D (400-800 IU) and Calcium (1000-1200 mg). This specific combination has been shown to significantly reduce hip fracture risk, whereas Vitamin D by itself does not.

Higher blood concentrations of 25-hydroxyvitamin D (25[OH]D) are associated with lower risks of fracture in observational studies, but this association is not replicated when using vitamin D supplementation alone in randomized trials.

Don't rely on Vitamin D alone to protect your bones. While people with naturally high Vitamin D levels have fewer fractures, taking Vitamin D supplements by themselves does not reduce fracture risk. You need to combine it with Calcium to see benefits.

Consuming broccoli or glucoraphanin-rich sources provides health benefits primarily through the formation of sulforaphane, but efficacy depends on the bioavailability of the source and individual microbiome capacity to convert glucoraphanin to sulforaphane.

To get the most benefit from broccoli, focus on getting enough glucoraphanin. This means choosing broccoli varieties known to be high in this compound (like certain sprouts or specific hybrids) rather than just any generic head. If you take supplements, be aware that sulforaphane is unstable, so look for stabilized formulations. Your gut bacteria play a key role in converting the precursor to the active form, so individual results may vary.

Consumption of prebiotics (specifically inulin-type fructans) and probiotics reduces serum total and LDL cholesterol levels in hypercholesterolemic or dyslipidemic individuals.

Adding prebiotic fibers like inulin or probiotic-enriched foods to your diet can help lower bad cholesterol (LDL) and total cholesterol levels in people with high cholesterol.

Omega-3 fatty acid supplementation and consumption increase adiponectin levels, particularly in individuals with low basal levels, improving metabolic and oxidative profiles.

Consider increasing your intake of omega-3 fatty acids through fish oil supplements or omega-3 rich foods like fish. This can significantly raise your adiponectin levels, especially if your baseline levels are low, leading to better lipid and glucose metabolism.

Mineral deficiencies (specifically Magnesium, Zinc, Iron, Copper, and Selenium) impair immune competence by disrupting innate and adaptive immune cell function and inflammation regulation, whereas maintaining adequate levels through a balanced diet supports optimal immune defense.

Focus on eating a varied diet rich in vegetables, nuts, seeds, whole grains, and lean proteins to naturally cover your mineral needs. You likely do not need supplements unless you are in an at-risk group (like an athlete with a restricted diet, elderly, or pregnant) or have a diagnosed deficiency. If you do supplement, do so under medical guidance to avoid toxicity, as too much of certain minerals (like Iron or Zinc) can actually harm your immune system or feed pathogens.

Magnesium deficiency promotes a pro-inflammatory state by increasing cytokine production (IL-6, TNF-alpha) and oxidative stress, while adequate Magnesium levels help regulate inflammation and support T-cell function.

If you have chronic low-grade inflammation, check your Magnesium levels. Ensuring adequate intake through foods like spinach, nuts, and seeds may help lower inflammatory markers like CRP. Do not self-prescribe high-dose supplements without testing, as balance is key.

Zinc supplementation (>75 mg/day) significantly reduces the duration of common colds, and adequate Zinc status is critical for T-cell maturation and preventing thymic atrophy, though excessive doses (>40 mg/day long-term) can cause immune dysfunction.

If you catch a cold, starting Zinc lozenges or supplements (totaling >75mg/day) within 24 hours may shorten the illness. Do not take high-dose Zinc (over 40mg/day) as a daily long-term supplement, as it can harm your immune system and cause other health issues. Get your Zinc from food sources like beef, oysters, and nuts instead.

Direct supplementation with EPA and DHA is significantly more effective for cardiovascular health and raising the n-3 index than consuming alpha-linolenic acid (ALA) from plant sources, due to the extremely low and variable bioconversion rate of ALA to EPA/DHA in humans.

If your goal is cardiovascular protection or raising your blood omega-3 levels, direct sources of EPA and DHA (from fish or algae supplements) are far more effective than relying on plant sources like flax or chia seeds. Your body converts very little of the plant-based ALA into the active EPA and DHA needed for these benefits. Vegans should prioritize algae-based EPA/DHA supplements to ensure adequate intake.

Stearidonic acid (SDA) is a more effective plant-based precursor for increasing EPA levels than alpha-linolenic acid (ALA) because it bypasses the rate-limiting delta-6-desaturase enzyme step in the conversion pathway.

If you cannot take fish or algae oil, look for supplements containing Stearidonic Acid (SDA) from sources like Echium plantagineum or Buglossoides arvensis (Ahiflower). These provide more EPA than equivalent amounts of standard flax or chia oil because they skip the hardest step of conversion in your body.

Genetic variants in the FADS1-2-3 gene cluster significantly reduce the bioconversion of ALA to EPA/DHA, making direct EPA/DHA supplementation necessary for populations with high prevalence of these variants (e.g., Americans, East Asians).

If you are of American or East Asian descent, your body is genetically less efficient at converting plant omega-3s (flax/chia) into active forms. You should prioritize direct sources of EPA and DHA (fish or algae oil) to ensure you get the benefits, whereas South Asian or African populations may have better conversion efficiency from plant sources.