Stiff, sore muscles might be a sign that your daily diet is missing key nutrients. Vitamins help keep your muscles and movement healthy and flexible. Your body cannot store most vitamins, but you can replenish them from the foods you eat. Deficiencies of some vitamins and minerals can directly or indirectly affect your muscles, causing stiffness, cramps, weakness and other symptoms.
Your body requires at least 2.4 micrograms of vitamin B-12 every day; sources include meat, milk and dairy products. This vitamin plays a critical role in producing healthy red blood cells that carry oxygen and nutrients to your muscles and tissues. Low levels of red blood cells can deprive muscles of oxygen, leading to weakness, numbness and difficulty walking. A deficiency of vitamin B-12 also can affect nerves, causing tingling in your feet and hands.
Muscle fibers are made from proteins, and nutrients such as pyridoxine -- vitamin B-6 -- help to maintain the function of proteins in your body. Your body also needs this vitamin for healthy red blood cells and nerves. MedlinePlus notes that vitamin B-6 helps treat conditions such as sore muscles and nighttime leg cramps. Adults need a daily dose of 80 to 100 milligrams of vitamin B-6; sources include whole grains, meat, liver, beans, eggs and vegetables.
Vitamin D helps your body absorb and use calcium, a mineral that is essential for bone, nerve and muscle health, and it helps to balance thyroid hormone levels. The Linus Pauling Institute notes that a vitamin D deficiency can lead to muscle pain and weakness in adults and children. Most adults require 600 international units of vitamin D a day. Only a few foods, such as fatty fish and fish liver oils, naturally provide vitamin D, but most milk and some eggs are fortified with it. Your body can produce adequate amounts of vitamin D when you expose bare skin to sunlight for short periods a few times a week, notes the Linus Pauling Institute.
Like vitamins, minerals are essential for good muscle health and overall well-being. A 2004 review published in the journal "Nutrition" reports that even slight deficiencies in some minerals can lead to impaired muscle health. Iron is necessary for your body to produce red blood cells, so a deficiency can lead to reduced muscle function and strength. A magnesium deficiency increases the amount of oxygen your muscles need for even lower-level exercise and also reduces muscle performance. Good sources of iron include red meat, poultry, eggs and green leafy vegetables, while magnesium is found in spinach, broccoli, legumes, whole-wheat bread and milk.