The Soyfoods Association of North America stated in their May 10, 2002 written testimony titled "Comments on Soymilk (Soy Milk) in Child Nutrition and WIC Programs," submitted to the United States Department of Agriculture (USDA):
soymilk (soy milk) is a good source of protein, calcium, and vitamin D,
as well as many other vitamins and minerals. These nutrients appear in
soymilk (soy milk) in levels similar to that of cow’s milk... In
addition, studies have found that in comparison with animal protein,
soy protein decreases calcium excretion, presumably due to the lower
sulfur amino acid content of soy protein. Consequently, a soy-based
diet is able to maintain calcium balance with a lower calcium intake."
Yongdong Zhao, MD, PhD, Postdoctoral Research Fellow at Children's Memorial Research Center et al., discussed whether humans can absorb calcium from soy milk fortified with calcium carbonate as well as the calcium from cow's milk in their Oct. 2005 paper "Calcium Bioavailability of Calcium Carbonate Fortified Skim Milk Is Equivalent to Cow's Milk in Young Women," published in The Journal of Nutrition:
absorption efficiency is similar for CCSM [calcium carbonate fortified
soy milk] and cow's milk in premenopausal women. The 3 cups (710 mL) of
cow's milk daily recommended by the 2005 Dietary Guidelines would
provide 855 mg total calcium and 186 mg absorbable calcium in our study
population. The same amount of calcium-fortified soymilk would provide
1104 mg total calcium with 233 mg absorbable calcium if CC [calcium
carbonate] were the fortificant and 200 mg absorbable calcium if TCP
[tricalcium phosphate] were the fortificant... Thus, the extra calcium
used to fortify soymilk makes up for the reduced bioavailability when
TCP is used as the fortificant. All 3 beverages are good sources of
calcium provided that the fortificant remains well dispersed and is
Jackie Newgent, a registered dietician, explained in her article "Are Dairy Alternatives Good For Your Bones?" (available on the Discovery Health website; accessed Apr. 12, 2007):
as with milk, there are varying fat and calorie contents for milk
alternatives. Most are lower in protein than milk, but since they're
all plant-based, no milk alternative contains cholesterol. Vitamins and
minerals are added to many of the alternatives, making them
nutritionally similar to milk.
few have more calcium and vitamin D than milk! In particular, soy
'milk' has the added advantage of isoflavones, known as phytoestrogens.
Though the jury is still out on phytoestrogens, these substances may
mimic estrogen and contribute to the slowing of bone loss due to
decreasing estrogen levels associated with menopause."
The Dairy Council of California stated in their online article "Milk Facts - Dispelling the Milk Myths," (accessed Apr. 12, 2007):
"Soy-based beverages are not
nutritionally equivalent to milk. Fortified soymilk may contain the
same amount of calcium in cow's milk on the label, but you have to
drink more of it to get the same benefits because the amount of calcium
the body absorbs is less... The body absorbs about 25 percent less
calcium from soymilk than from cow's milk.
Since soy beverages are
naturally low in calcium (about 10 milligrams per serving),
manufacturers fortify them with calcium salts to boost the calcium
content. However, the amount of calcium salts added is not regulated
and may vary from 80 to 500 milligrams a serving. A serving of milk (8
ounces) contains about 300 milligrams of calcium.
It would take 500
milligrams of calcium in an 8-ounce serving of fortified soymilk to
equal the calcium in a glass of cow's milk."
Robert Heaney, MD, John A. Creighton University Professor in the Department of Medicine at Creighton University et al., wrote in their article "Bioavailability of the Calcium in Fortified Soy Imitation Milk, With Some Observations on Method," published Jan. 2000 in the American Journal of Clinical Nutrition:
"Calcium from intrinsically labeled soy milk was absorbed at only 75% the efficiency of calcium from cow milk. Extrinsic labeling [calcium fortification] of soy milk... resulted in a 50% overestimate of true absorbability.
Our findings show that calcium fortification of soy milk, at least by some producers, does not result in a calcium source comparable to cow milk in terms of either physical properties or absorbability."
Elizabeth Weise, a journalist, reports in her Feb. 14, 2005 article in USA Today titled "Consumers May Miss Needed Calcium":
calcium actually available in some popular soy and rice drinks can be
as much as 85% lower than the amount on the product label. It's not
that the drinks do not contain the calcium listed on the label, an
omission that would violate the Food and Drug Administration's labeling
requirements... Calcium can settle out of soy and rice beverages,
forming a calcium sludge at the bottom of the carton that does not
always make it into the consumer's mouth. So the moral of this story is
that shaking before pouring is crucial."