Browse the evidence

Selenium deficiency impairs immune response to viral infections, potentially increasing viral virulence and disease severity, particularly for RNA viruses like Coxsackievirus B3 and HIV.

For those with chronic viral infections like HIV, maintaining adequate selenium levels through diet or supplementation (if deficient) may support immune cell counts and potentially slow disease progression, though it is not a cure. For general viral prevention, ensuring adequate selenium is a baseline requirement for a functional immune system.

Coffee consumption (>3 cups/day) has a protective role and improves liver enzymes in individuals at risk of liver diseases.

Drinking more than 3 cups of coffee daily may help protect liver health and improve enzymes.

The protective effect of high folate intake against coronary heart disease is significantly stronger in women who consume alcohol, particularly those drinking more than one drink per day.

If you are a woman who drinks alcohol, ensuring you have high levels of folate and vitamin B6 is particularly important. The study found that the heart-protective benefits of these vitamins were strongest in women who drank more than one drink per day. This suggests that alcohol consumers should pay extra attention to their B-vitamin intake, potentially through diet or supplements.

Some dietary supplements contain nutrients at or above the Upper Intake Levels (UL), posing a risk of excessive intake, especially when multiple supplements are used.

Check your supplement labels. Some contain nutrients at or above the Upper Intake Levels. Taking multiple supplements can increase the risk of exceeding safe limits.

Dried Moringa oleifera leaves serve as a high-quality nutritional supplement containing 30.3% crude protein, essential amino acids, and significant minerals, making them effective for improving animal health and nutrition.

Incorporate dried Moringa leaf powder into your diet or animal feed to boost intake of protein, iron, calcium, and vitamins. It is a nutrient-dense supplement that can help address deficiencies, particularly in protein and minerals.

Dietary fat co-ingestion significantly enhances the absorption of quercetin aglycone supplements.

Take quercetin aglycone supplements with a meal containing fat to maximize absorption. Studies show high-fat meals can increase plasma quercetin concentration by 45% compared to fat-free meals.

Omega-3 fatty acid supplementation reduces pro-inflammatory cytokines (e.g., IL-6) and may improve outcomes in viral infections, though excessive inflammation reduction during active infection could potentially be detrimental.

Consider supplementing with Omega-3 fatty acids (1.25-2.5g/day) to help manage inflammation. While generally beneficial, be aware that the timing of supplementation relative to an active infection might matter, as excessive anti-inflammatory effects could theoretically interfere with necessary immune responses.

Kefir consumption improves lactose digestion and reduces flatulence severity in individuals with lactose malabsorption, performing similarly to plain yogurt.

If you get bloated or gassy from milk, try kefir. It contains natural enzymes that break down the lactose, so you get the nutrients without the stomach upset. One study showed it caused less gas than milk and was just as easy to handle as yogurt.

Selenium supplementation reduces liver cancer incidence by 35% in a community with low baseline selenium status, but may increase the risk of type 2 diabetes in individuals with high baseline plasma selenium levels.

In selenium-deficient populations, supplementation (e.g., 200 μg/day) can significantly reduce liver cancer risk. However, individuals with high baseline selenium levels should avoid supplementation due to an increased risk of type 2 diabetes.

Branched-chain amino acid (BCAA) supplementation can improve exercise performance and recovery, particularly in aerobic exercise and slower runners.

If you do long-distance running, BCAAs might help you feel less fatigued. You can take them before or during your run, or just eat whey protein or whole foods which naturally contain BCAAs.

Zinc supplementation (45 mg elemental Zn gluconate/day for 12 months or 25 mg zinc sulfate/day for 3 months) improves immune function in older adults by increasing activated T helper and cytotoxic T lymphocytes and reducing infection incidence.

If you are an older adult, ensuring adequate zinc intake through supplementation (e.g., 25-45 mg/day) may help boost your immune response and reduce infections, as shown in clinical trials. However, results can vary, so consult a doctor before starting high-dose zinc.

Restoring deficient micronutrients (Vitamins A, C, D, E, B2, B6, B12, folic acid, iron, selenium, zinc) to recommended levels improves immune function and increases resistance to infection.

If you suspect you are deficient in key immune-supporting nutrients (like Vitamin D, Zinc, or Vitamin C), getting your levels checked and restoring them to the recommended range is a proven way to support your immune system. This is especially important for infants, the elderly, and those with restricted diets, as food alone may not provide enough of these specific nutrients to maintain optimal immune defense.

Micronutrient deficiencies (specifically Zinc, Vitamin A, Iron, Selenium) impair both innate and adaptive immune responses, increasing susceptibility to infections like pneumonia, diarrhea, and measles.

Ensure your diet includes sources of Zinc, Vitamin A, Iron, and Selenium, especially if you are caring for young children or are elderly. If you have a restricted diet or known absorption issues, consider that food alone might not be enough to support full immune competence, and professional guidance on supplementation may be beneficial.

Vitamin D3 (cholecalciferol) supplementation significantly reduces all-cause mortality in adults, particularly in elderly populations, whereas Vitamin D2, alfacalcidol, and calcitriol do not show significant mortality benefits.

If you are considering Vitamin D for longevity, choose Vitamin D3 (cholecalciferol). This large review of nearly 100,000 people found that D3, but not D2 or active forms, significantly reduced the risk of death, especially in older adults. The benefit is modest (about 150 people need to be treated for 5 years to save one life), but it is a low-risk intervention for this demographic. Be aware that combining D3 with calcium may slightly increase kidney stone risk.

Vitamin D3 supplementation significantly reduces cancer-specific mortality.

Vitamin D3 may help reduce the risk of dying from cancer. This finding is based on a smaller subset of trials than the general mortality benefit, so it should be viewed as a potential secondary benefit rather than the primary reason for supplementation. The reduction is statistically significant but modest.

Vitamin D3 supplementation may significantly reduce diabetes risk in individuals with severe vitamin D insufficiency (baseline <12 ng/mL), although this finding is from a post hoc subgroup analysis.

If you are severely vitamin D deficient (levels <12 ng/mL), supplementation with 4000 IU of Vitamin D3 daily might significantly lower your diabetes risk. However, this was a small subgroup analysis, so consult your doctor to check your levels before relying on this.

Selenium acts as a protective agent in pathological processes including cancer, muscular diseases, coronary heart disease, and viral infections (influenza, HIV) through the function of selenoproteins in controlling cellular redox processes.

Ensure adequate selenium intake through diet or supplementation to support selenoprotein function, which is critical for protecting against oxidative stress, supporting immune response to viruses, and maintaining heart and muscle health. Consult a healthcare provider for appropriate dosing, as requirements vary.

Short-chain fatty acids (SCFAs), particularly butyrate, produced by gut microbiota fermentation of fiber, have anti-inflammatory properties and improve insulin sensitivity, although their net effect in obesity is complex and context-dependent.

Increase intake of dietary fiber to promote the production of short-chain fatty acids (SCFAs) by gut bacteria, which supports insulin sensitivity and reduces inflammation. Start slowly to minimize digestive discomfort.

Red meat contains bioactive compounds such as taurine, carnitine, creatine, and endogenous antioxidants (carnosine, ubiquinone, glutathione) that may offer protective effects against oxidative stress and support muscle energy metabolism.

Red meat provides bioactive compounds like creatine, carnitine, and taurine that support muscle function and antioxidant defense. While you won't get therapeutic doses of isolated supplements from meat alone, it contributes to your overall intake of these beneficial compounds.

Low circulating levels of 25-hydroxyvitamin D are associated with a significantly higher risk of death from cardiovascular disease, cancer, and all-cause mortality in observational studies.

Maintaining adequate vitamin D levels is associated with a lower risk of death from heart disease and cancer. While this is an observational finding, ensuring sufficient levels through sensible sun exposure or supplementation is a low-risk strategy for long-term health.

Whole grains protect against cancer, particularly colon and breast cancer, through the action of antioxidants, lignans, and other bioactive compounds found in the bran and germ.

Include whole grains in your diet to reduce cancer risk. The bran and germ contain antioxidants, lignans, and phytic acid that protect cells from damage. These compounds are lost when grains are refined, so choose whole grain products to maximize these protective benefits.

L-carnitine supplementation ameliorates complications in uremic patients undergoing hemodialysis, including cardiac dysfunction, intradialytic hypotension, and erythropoietin-resistant anemia.

If you are on hemodialysis, your body likely loses carnitine during treatment, which can worsen heart function, cause low blood pressure during sessions, and make anemia harder to treat. Discussing L-carnitine supplementation with your nephrologist may help manage these specific complications, although you should be aware that clinical evidence is still evolving.

Acetyl-L-carnitine (ALC) supplementation improves nerve conduction, neuropathic pain, and immune function in diabetes patients, particularly in the early metabolic phase of diabetic polyneuropathy.

If you have diabetes and are experiencing early nerve pain or slowing nerve conduction, Acetyl-L-carnitine (ALC) may help improve nerve function and reduce pain by supporting mitochondrial health. However, this intervention is most effective in the early stages of nerve damage before structural changes become permanent.

High intake of flavonols and flavan-3-ols is associated with a reduced relative risk of ischaemic stroke (0.55 and 0.59 respectively) and potentially reduced CVD mortality in middle-aged men.

To potentially lower stroke risk, aim for a diet high in flavonoid-rich foods. This includes drinking tea, eating berries, apples, onions, and consuming cocoa. The study suggests that men in the highest intake groups had roughly half the risk of ischaemic stroke compared to those with the lowest intake.