Vitamin A
Supports vision, immune function, and skin health. Found in carrots, sweet potatoes, spinach, and liver. Deficiency can cause night blindness and increased infection risk.
B Vitamins (B1, B2, B3, B6, B12, Folate)
This group supports energy metabolism, nerve function, and red blood cell production. Found in whole grains, eggs, meat, legumes, and leafy greens. Vitamin B12 deficiency, more common in older adults and those on plant-based diets, can cause fatigue and nerve symptoms if untreated.
Vitamin C
Supports immune function, wound healing, and collagen production. Found in citrus fruits, peppers, and strawberries. Severe deficiency (scurvy) is rare today but mild insufficiency can affect healing and immunity.
Vitamin D
Essential for calcium absorption and bone health, and increasingly linked to immune function. The body produces it with sun exposure, and it's also found in fatty fish and fortified foods. Deficiency is common, especially with limited sun exposure, and can contribute to weakened bones over time.
Vitamin E
Acts as an antioxidant, protecting cells from damage. Found in nuts, seeds, and vegetable oils. True deficiency is uncommon in people eating a varied diet.
Vitamin K
Essential for normal blood clotting and supports bone health. Found in leafy greens like spinach and kale. Deficiency is rare in adults but relevant for people on certain blood-thinning medications, who should keep their intake consistent.
Everything in One Place
If you suspect a deficiency — persistent fatigue, hair loss, or unusual symptoms — our internal medicine and nutrition team can order the right blood tests and build a plan based on your actual levels, not guesswork.
Wondering if you have a vitamin deficiency? Ask about getting tested.
References
- National Institutes of Health, Office of Dietary Supplements — Vitamin fact sheets
- Harvard T.H. Chan School of Public Health — Vitamins overview
- Mayo Clinic — Vitamins and minerals
