Lupus (SLE)

Systemic lupus erythematosus (SLE) is an autoimmune disease in which the immune system attacks multiple organs, causing fatigue, joint pain, the characteristic butterfly facial rash, and flares that come and go unpredictably. It most often affects women of childbearing age and requires specialist rheumatology care with medications such as hydroxychloroquine. Vitamin D deficiency is common in lupus — partly because patients avoid sunlight — and correcting it is reasonable supportive care. Immune-stimulating supplements like echinacea and alfalfa should be avoided; alfalfa is specifically linked to lupus flares.

Evidence synthesis: The most consistent nutritional finding in SLE is widespread vitamin D deficiency, driven by sun avoidance, darker skin in affected populations, and corticosteroid use. Observational studies link low vitamin D to higher disease activity, and supplementation is recommended by the EULAR guidelines for bone health at minimum. Randomised trials of omega-3 fatty acids show modest reductions in disease activity in some but not all studies. Vitamin D trials show it is safe and improves serum levels, but direct evidence that it reduces flare rates remains inconsistent. Critically, supplements marketed as immune boosters (echinacea, alfalfa sprouts) have theoretical or documented flare-triggering risk.