Magnesium

Magnesium is a component of bone, giving it resiliency and protection against fractures; it also is essential for converting vitamin D to its active form in the body. If you take a calcium and vitamin D supplement, take magnesium, too, because high calcium intake causes magnesium loss, and most Americans don't consume enough magnesium.

Requirement for adults: 310-420 mg

Sources: Nuts, seeds, leafy green vegetables, whole grains and legumes.

Vitamin K

Vitamin K is found in two main forms in food, K1 and K2, and your body may convert limited amounts of vitamin K1 to K2. Both forms play a role in blood clotting (and work against the anti-clot drug warfarin), but vitamin K2 also helps prevent calcium from depositing in arteries (the process of atherosclerosis) and instead directs calcium to bones and helps bind the mineral to your skeleton.

Requirement for adults: 75-120 mcg (micrograms)

Sources: K1 is found in dark, leafy green vegetables such as kale and spinach; K2 is in natto (fermented soybeans), cheese, grass-fed meat and liver.

Vitamin B12 & Folate

Vitamin B12 and folate support bone health by helping to keep levels of homocysteine, a compound that stimulates the breakdown of bone, low. This role is further confirmed by genetic studies that reveal a link between an increased risk of osteoporosis in older adults and a common gene mutation (MTHFR C677T) that can lead to high homocysteine levels.

Requirement for adults: For folate, 400-600 mcg. For B12, 2.4 -2.8 mcg. (Your doctor may advise higher amounts if you have elevated homocysteine.)

Sources: B12 is in meat, fish and other animal foods, as well as in fortified foods, including cereals and nutritional yeast. Folate is in leafy green vegetables, broccoli, asparagus and legumes.

(Environmental Nutrition is the award-winning independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit www.environmentalnutrition.com.)