PROTECTING YOUR BONES . . .
by PCRM
The bone-thinning condition
called osteoporosis can lead to small and not-so-small
fractures. Although many people think of calcium in
the diet as good protection
for their bones, this is not at all the whole story.
In fact, in a 12-year Harvard study of 78,000 women,
those who drank milk three times a day actually broke more
bones than women who rarely drank milk.1 Similarly, a 1994
study of elderly men and women in Sydney, Australia, showed
that higher dairy product consumption was associated with
increased fracture risk. Those with the highest dairy
product consumption had approximately double the risk of
hip fracture compared to those with the lowest consumption.2
To protect your bones you do need calcium in your diet,
but you also need to keep calcium in your bones.
How To Get Calcium
Into Your Bones
1.
Get calcium from greens, beans, or fortified foods.
The
most healthful calcium sources are green leafy vegetables
and legumes, or “greens and beans” for short. Broccoli,
Brussels sprouts, collards, kale, mustard greens, Swiss
chard, and other greens are loaded with highly absorbable
calcium and a host of other healthful nutrients. The
exception is spinach, which contains a large amount
of calcium but tends to hold onto it very tenaciously,
so that you will absorb less of it. Beans are humble
foods, and you might not know that they are loaded
with calcium. There is more than 100 milligrams of
calcium in a plate of baked beans. If you prefer chickpeas,
tofu, or other bean or bean products, you will find
plenty of calcium there, as well. These foods also
contain magnesium, which your body uses along with calcium
to build bones.
If you are looking for a very concentrated calcium source,
calcium-fortified orange or apple juices contain 300 milligrams
or more of calcium per cup in a highly absorbable
form. Many people prefer calcium supplements, which are
now widely available. Dairy products do contain calcium,
but it is accompanied by animal proteins, lactose sugar,
animal growth factors, occasional drugs and contaminants,
and a substantial amount of fat and cholesterol in all
but the defatted versions.
2.
Exercise, so calcium has somewhere to go.
Exercise
is important for many reasons, including keeping bones
strong. Active people tend to keep calcium in their
bones, while sedentary people lose calcium.
3. Get vitamin D from the sun, or supplements if you
need them.
Vitamin D controls your body’s use of calcium. About
15 minutes of sunlight on your skin each day normally
produces all the vitamin D you need. If you get little
or no sun
exposure, you can get vitamin D from any multiple vitamin.
The Recommended Dietary Allowance is 200 IU (5 micrograms)
per day. Vitamin D is often added to milk, but the
amount added is not always well controlled.
How To Keep It
There
It’s
not enough to get calcium into your bones. What is
really critical is keeping it there. Here’s how:
1. Reduce
calcium losses by avoiding excess salt.
Calcium
in bones tends to dissolve into the bloodstream, then
pass through the kidneys into
the urine. Sodium (salt) in the foods you eat can greatly
increase calcium loss through the kidneys.3 If you
reduce your sodium intake to one to two grams per day,
you will hold onto calcium better. To do that, avoid
salty snack foods and canned goods with added sodium,
and keep salt use low on the stove and at the table.
2. Get
your protein from plants, not animal products.
Animal
protein—in fish, poultry, red meat, eggs, and dairy
products—tends to leach calcium from the bones and
encourages its passage into the urine. Plant protein—in
beans, grains, and vegetables—does not appear to have
this effect.4
3. Don’t
smoke. Smokers lose calcium,
too.
A study of identical twins showed that, if one
twin had been a long-term smoker and the other had
not, the smoker had more than a 40 percent higher risk
of a fracture.5 American recommendations for calcium
intake are high, partly because the meat, salt, tobacco,
and physical inactivity
of American life leads to overly rapid and unnatural
loss of calcium through the kidneys. By controlling
these basic factors, you can have an enormous influence
on whether calcium stays in your bones or drains out
of your body.
Hormone
Supplements Have Serious Risks
Some
doctors recommend estrogen supplements for women after
menopause as a way to slow osteoporosis, although the
effect is not very great over the long run, and
they are rarely able to stop or reverse bone loss. Many
women find these hormones distasteful because the most
commonly prescribed brand, Premarin, is made from
pregnant mares’ urine, as its name suggests. What
has many physicians worried is the fact that estrogens
increase the risk of breast cancer. The Harvard Nurses’
Health Study found that women taking estrogens have 30
to 80 percent more breast
cancer, compared to other women.6
Moreover, Premarin may aggravate heart problems.
In a study of 2,763 postmenopausal women with coronary
disease followed for an average of four years, there
were as many heart attacks and related deaths in women
treated with the
combined regimen of estrogens and a progesterone
derivative, as with placebo, but the coronary problems
occurred sooner in women taking hormones. Hormone-treated
women were also more likely to develop dangerous
blood clots and gallbladder disease.7 Controlling calcium
losses is a much safer strategy.
Reversing Osteoporosis
If
you already have osteoporosis, you will want to speak
with your doctor about exercises and perhaps even
medications that can reverse it.
Osteoporosis in Men
Osteoporosis
is less common in men than in women, and its causes
are somewhat different. In about half
the cases, a specific cause can be identified
and addressed:8
• Steroid medications, such as prednisone,
are a common cause of bone loss and fractures. If you
are
receiving steroids, you will want to work with
your doctor to minimize the dose and to explore other
treatments.
• Alcohol can weaken your bones, apparently by
reducing the body’s ability to make new bone
to replace normal losses. The effect is probably only
significant if you have
more than two drinks per day of spirits, beer,
or wine.
• A lower than normal amount of testosterone
can encourage osteoporosis. About 40 percent
of men over 70 years of age have decreased levels of
testosterone. In many of the remaining cases, the causes
are excessive calcium losses and inadequate vitamin D.
The first part of the solution is to avoid animal protein,
excess salt and caffeine,
and tobacco, and to stay physically active in
order to reduce calcium losses. Second, take
vitamin D supplements as prescribed by your physician.
The usual amount is 200
IU (5 micrograms) per day, but it may be doubled
if you get no sun exposure at all. If you have
trouble absorbing calcium due to reduced stomach acid,
your doctor can recommend hydrochloric acid supplements.
Calcium And Magnesium
In Foods (in mg)
Calcium Magnesium
- Collards (1 cup, boiled) 358 52
- Orange
juice,
- calcium-fortified (1 cup) 350*
—
- Oatmeal, instant (2 packets) 326
70
- Figs, dried (10 medium) 269 111
- Tofu,
calcium-set (1/2 cup) 258 118
- Spinach (1 cup, boiled)
244 158
- Soybeans (1 cup, boiled) 175 148
- White
beans (1 cup, boiled) 161 113
- Mustard greens (1
cup, boiled) 150 20
- Navy beans (1 cup, boiled) 128
107
- Vegetarian baked beans (1 cup)
128 82
- Great northern beans (1 cup, boiled)
121 88
- Black turtle beans (1 cup, boiled)
103 91
- Swiss chard (1 cup, boiled) 102
152
- Broccoli (1 cup, boiled) 94 38
- Kale
(1 cup boiled) 94 24
- English muffin 92 11
- Butternut squash
(1 cup, boiled) 84 60
- Pinto beans (1 cup, boiled)
82 95
- Chick peas (1 cup, canned) 80 78
- Sweet
potato (1 cup, boiled) 70 32
- Green beans (1 cup,
boiled) 58 32
- Barley (1 cup) 57 158
- Brussels sprouts
(8 sprouts) 56 32
- Navel orange (1 medium) 56 15
- Raisins
(2/3 cup) 53 35
Source: J.A.T. Pennington, Bowes and Church’s
Food Values of Portions
Commonly Used. (Philadelphia: J.B. Lippincott,
1994.)
*Information from manufacturer
References
1. Feskanich
D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary
calcium, and bone fractures in women: a 12-year
prospective study. Am J Publ Health 1997;87:992-7.
2. Cumming RG, Klineberg RJ. Case-control
study of risk factors for hip fractures
in the elderly. Am J Epidemiol 1994;139:493-503.
3. Nordin BEC, Need AG, Morris HA, Horowitz
M. The nature and significance of the
relationship between urinary sodium and urinary calcium
in women. J Nutr 1993;123:1615-22.
4. Remer T, Manz F. Estimation of the
renal net acid excretion by adults consuming
diets containing variable amounts of protein. Am J Clin
Nutr 1994;59:1356-61.
5. Hopper JL, Seeman E. The bone density
of female twins discordant for tobacco
use. N Engl J Med 1994;330:387-92.
6. Colditz GA, Stampfer MJ, Willett WC,
et al. Type of postmenopausal hormone
use and risk of breast cancer: 12-year follow-up from the
Nurses’ Health Study. Cancer Causes and Control
1992;3:433-9.
7. Hulley S, Grady D, Bush T, et al.
Randomized trial of estrogen plus progestin
for secondary prevention of coronary heart disease in postmenopausal
women. JAMA 1998;280:605-13.
8. Peris P, Guanabens N, Monegal A, et
al. Aetiology and presenting symptoms
in male osteoporosis. Br J Rheumatol 1995;34:936-41.