Calcium needs change over one’s lifetime, with the greatest needs during childhood,
adolescence, pregnancy, and breastfeeding. Postmenopausal women and older men
may also need to consume more calcium. Ingestion of high levels of salt, sugar,
caffeine, alcohol, and exposure to nicotine increases calcium loss. Studies show
that fruit and vegetable intake is positively associated with increased bone density
in men and women.
There has been concern that excessive consumption of animal protein creates a
heavy acid load in the blood that requires mobilization of calcium from bone to neutralize it and increases the loss of calcium in the urine.34 However, a longitudinal
study and a review of 61 studies found that higher intakes of protein from plant or
animal sources did not have adverse effects on bone health in premenopausal women.
However, some analyses suggest that low vegetable protein intake is associated
with lower bone mineral density.
A 2017 meta-analysis that included 16 randomized controlled trials and 20 prospective
cohort studies concluded that there were no adverse effects from high protein
intake on bone, and only the lumbar spine showed moderate evidence to support a
protective benefit from high protein intake. The authors noted that the studies were
so diverse that confounding could not be excluded and that additional studies were
needed to clarify dietary protein’s role in bone health.
Osteoporosis is common in the U.S., even with relatively high consumption of milk
and other calcium-rich dairy products. Although consumption of milk is advocated
as a way to avoid osteoporosis, studies about the usefulness of milk in the prevention
of osteoporosis have found conflicting results. For example, a 20-year
study conducted in Sweden found that women who drank more than three glasses of
milk a day were more likely to suffer a broken bone and were at twice the risk of dying
at the end of the study than those who drank less. A similar but less pronounced
trend was found in men. However, an opposite pattern was found for fermented
milk products, such as yogurt, suggesting a role of the sugars in milk.
An inadequate supply of calcium from a diet low in calcium and vitamin D over
a lifetime also contributes to the development of osteoporosis. Studies in
children and adolescents have shown that supplementation with calcium, dairy calcium-
enriched foods, or milk enhances the rate of bone mineral acquisition. Many
studies show that low calcium intake appears to be associated with low bone mass,
rapid bone loss, and high fracture rates. Some studies show that vitamin D supplementation
can reduce rates of bone loss and also fracture rates in older male and
female adults, and the elderly. In institutionalized elderly women, this combined
calcium and vitamin D supplementation reduced hip fracture rates. For example,
the Nurses’ Health Study found that older women who consumed at least 500 IU of
vitamin D were one-third less likely to suffer a broken hip than women who got less
than 200 IU per day.
Other studies have found that calcium and vitamin D supplementation has little
effect on fracture risk. A trial randomly assigned more than 36,000 postmenopausal
women between the ages of 50 and 79 to receive 500 mg of elemental calcium as
calcium carbonate with 200 IU of vitamin D3 twice daily or matching placebos for
an average of seven years. Annualized rates of hip, total, and site-specific fractures
were the same for each of the groups, and the calcium with vitamin D supplementation increased the risk of kidney stones (renal calculi) by 17%.
Some of the differences in results of studies of vitamin D supplementation and fractures
may relate to the dose of vitamin D. A meta-analysis that included five randomized
controlled trials (RCTs) for hip fracture and 7 RCTs for nonvertebral fracture
risk found that a vitamin D dose of 700 to 800 IU/day reduced the relative risk
of hip fracture by 26% and any nonvertebral fracture by 23%. No significant benefit
was observed for RCTs with 400 IU/day vitamin D. The study authors concluded
that oral vitamin D supplementation between 700 to 800 IU/d appears to reduce the
risk of hip and any nonvertebral fractures in ambulatory or institutionalized elderly
persons and a vitamin D dose of 400 IU/d is not sufficient for fracture prevention.
However, a 3-year study of high-dose vitamin D at 4000 IU/day or 10,000 IU/day
compared to the usual dose of 400 IU per day found that the higher doses resulted
in lower bone density and provided no advantage over the 400 IU/day.
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.