Nutrition provides the substrates and cofactors that immune cells need to develop and function well. Adequate intake of micronutrients such as zinc, selenium, vitamins A, C, D, and iron supports barrier integrity and both innate and adaptive immune responses. When someone is malnourished or deficient in these nutrients, immune defenses weaken and infection risk rises. However, supplements for everyone to prevent infections aren’t supported by the evidence and can be unnecessary or even harmful in people who are already well-nourished. Supplementation is most beneficial when there is a deficiency, when someone is at high risk for deficiency, or in specific clinical situations. In the general population, the best strategy is a balanced, nutrient-rich diet that meets energy and micronutrient needs, along with other measures like vaccination, adequate sleep, stress management, and good hygiene to reduce infection risk.

Guidance on nutrition labeling emphasizes limiting nutrients that can harm health when consumed in excess. Added sugars and sodium are the typical targets because excess added sugars contribute extra calories with little nutritional benefit, linked to obesity and metabolic issues, while high sodium intake is tied to elevated blood pressure and cardiovascular risk. Labels often highlight these so consumers can compare products and choose lower amounts, helping to curb intake of calories from sugar and salt. In contrast, nutrients like protein, potassium, fiber, and calcium are generally nutrients to obtain more of or ensure adequate intake, not to reduce, and water isn’t a nutrient value shown for reduction on standard labels.

Fiber is the main nutrient gap people often encounter on gluten-free diets, with enrichment (the addition of vitamins and minerals to foods) also frequently missing. This happens because many gluten-free products are made from refined starches like white rice, corn, or potato starch, which naturally have little fiber and aren’t always fortified to the same extent as enriched wheat products. To address this, focus on fiber-rich, naturally gluten-free foods such as vegetables, fruits, legumes, nuts, seeds, and gluten-free whole grains like quinoa, buckwheat, millet, amaranth, and brown rice. Pair that with fortified gluten-free products when available to boost iron, B vitamins, and other nutrients. Regular dietary planning and guidance from a healthcare professional, plus periodic labs to check nutrient status, help tailor any needed adjustments.

In CKD, managing potassium and phosphorus is crucial because the kidneys’ ability to excrete these minerals declines as kidney function worsens. As GFR drops, potassium can accumulate in the blood, raising the risk of dangerous heart rhythms, while phosphorus can build up and contribute to bone and vascular problems. To prevent these issues, dietary restrictions for potassium and phosphorus are adjusted based on the stage of CKD and the person’s lab values; earlier stages may require milder limits, and more severe restrictions are used as kidney function declines or when lab abnormalities appear. This stage-dependent approach helps keep electrolyte levels in a safer range and supports overall health. Other nutrition aspects matter too: energy intake needs to be adequate to prevent malnutrition, and protein intake is generally moderated rather than unlimited to reduce waste build-up while preserving lean body mass. But no dietary restrictions at all would miss the key risk signals CKD presents.