Calcium
Calcium and bone health
Your bones are living tissues and continue to change throughout life. During childhood and adolescence, bones increase in size and mass. Bones continue to add more mass until around age 30, when peak bone mass is reached. Because bone loss, like bone growth, is a gradual process, the stronger your bones are at age 30, the more your bone loss will be delayed as you age.
It is particularly important to consume adequate calcium and
vitamin D
throughout your younger years. The National Institutes of Health also recommends
weight-bearing exercise
to maximize bone strength and bone density and to
help prevent osteoporosis. Osteoporosis is a disorder
characterized by porous, fragile bones. 80% of osteoporosis sufferers are women, and it affects
over 10 million Americans total.
A condition called "osteopenia" (low bone mass) proceeds osteoporosis, and affects another 30+ million Americans. Osteoporosis has association with bone fractures. Each year, Americans suffer from well over a million bone fractures because of the condition.
Both osteoporosis and osteopenia can result from low calcium intake or absortion. Low vitamin D intake also contributes to osteporosis. Bone loss also occurs as a part of the aging process. A prime example is the loss of bone mass observed in post-menopausal women because of decreased amounts of the hormone estrogen. Researchers have identified many factors that increase the risk for developing osteoporosis. Some key factors include family history, smoking cigarettes, being female, thin, inactive, of advanced age, and excessive alcohol use.
Although osteoporosis affects people of different races, genders and ethnicities, women are at highest risk because their skeletons are smaller to start with and because of the accelerated bone loss that accompanies menopause. Adequate calcium and vitamin D intakes, as well as weight-bearing exercise are critical to the development and maintenance of healthy bone throughout the lifecycle. Older adults should strive to maintain recommended daily calcium intakes as well as an adequate vitamin D intake.
Great sources of calcium Include:
- Plain low-fat yogurt (8 oz): 415 mg calcium, 42% of the Daily Value (DV)
- An 8-oz glass of milk, 300 mg, or 1 1/2 oz. of shredded cheddar cheese: 300 mg, about 30% of DV
- A cup of cooked spinach: 240 mg (24% DV)
- Cottage cheese, salmon, calcium-fortified orange juice and breakfast cereals
It can be difficult to obtain enough vitamin D from natural food sources. For many people, consuming vitamin D fortified foods and adequate sunlight exposure are essential for maintaining a healthy vitamin D status. In some groups, dietary supplements may be needed to meet the daily need for vitamin D.
Infants who are exclusively breastfed
In infants, vitamin D requirements cannot be met by human (breast) milk alone, which usually provides approximately 25 IU vitamin D per liter. The American Academy of Pediatrics (AAP) recommends a daily supplement of 200 IU vitamin D for breastfed infants beginning within the first two months of life unless they are weaned to receive at least 500 ml (about 2 cups) per day of vitamin D-fortified formula. Children and adolescents who are not routinely exposed to sunlight and do not consume at least 2, 8-fluid-ounce servings of vitamin D-fortified milk per day are also at higher risk of vitamin D deficiency and may need a dietary supplement containing 200 IU vitamin D.
Older adults
As people age, skin cannot synthesize vitamin D as efficiently and the kidney is less able to convert vitamin D to its active hormone form. Americans age 50 and older are believed to be at increased risk of developing vitamin D deficiency. 30% to 40% of older adults with hip fractures are believed to be vitamin D insufficient. Therefore, older adults may benefit from supplemental vitamin D.