One of the most common nutritional myths is that you must eat dairy
products to get enough calcium. Milk holds a special place in American
culture, next to apple pie and mother. The dairy industry has convinced
most of us that we can't live without their products, but there is ample
evidence that we can live longer, feel better and have as much strength
without milk, cheese, yogurt and all other dairy products.
Most of the calcium in the body is in our bones, with a small amount
in the blood stream to aid in regulating the heartbeat, transmission of
nerve impulses and muscle contraction. The amount of calcium in the
blood is controlled by hormones. Calcium is continuously lost through
body waste and sweat, and is replaced with calcium from the bones. As a
process of normal tissue growth, the body constantly breaks down bone
material and rebuilds it, using calcium from foods for replacement
Keeping bones strong depends more on preventing calcium loss than on
increasing calcium intake. In nations with high rates of osteoporosis,
protein intake is generally more than twice the U.S. Recommended Daily
Allowance. Diets that are high in protein, especially animal protein,
cause calcium to be lost through the urine. Meats are high in a
particular kind of protein building block, called sulfur-containing
amino acids, that cause increased calcium loss. Studies show that
vegetarians have less than half the amount of osteoporosis that meat
eaters have. Caffeine and sodium also increase the rate of calcium loss
through urine. Alcohol inhibits calcium absorption and may also be toxic
to bone. We can benefit from boron, found in fruits, vegetables, and
beans, since it appears to help stop the loss of calcium. Vitamin D,
copper, zinc, and weight training exercise also may increase bone mass
and help to prevent osteoporosis.
The need for calcium varies at different ages. For the first 35 years
our bodies lose less calcium than we consume. After 45, our body
gradually loses more calcium than is taken in. The rate of calcium loss
depends on how much and what kind of protein we consume. A negative
calcium balance can result in osteoporosis, or fragile bones.
The body regulates how much calcium it absorbs, usually between 30%
and 70% for a normal diet. If a person eats more calcium, the body just
doesn't absorb it. This is a reason why high doses of calcium
supplements may not prevent bone loss.
Milk is not the ideal way to get your daily supply of calcium. Milk
(except skim) is high in saturated fat. It also contains high amounts of
calcium-blocking protein. In addition, antibiotics fed to cows are
passed on in about one third of milk sold in America. Bovine Growth
Hormone is now allowed to be given to dairy cows to increase their milk
supply. This hormone, usually combined with greater amounts of
antibiotics, has not been subjected to long-term human testing. Although
they often don't realize it, most people (about 75% of the U.S.
population) have an allergy to cow's milk, called lactose intolerance.
As infants, our body makes an enzyme called lactase, allowing us to
metabolize the milk sugars (lactose). After childhood most people no
longer make this enzyme necessary to digest dairy products properly.
Human breast milk provides all the calcium a child needs and has only 6%
of calories from protein, far less than the 22% in cow's milk, which is
the amount needed for a calf to grow quickly. Dark green leafy
vegetables are a much better source of calcium than milk, and they have
almost no fat and much lower amounts of protein. Some plant sources of
calcium are shown in the section
Plant Sources of Calcium.