The medical dictionary describes "frailty" as "a state of delicacy or weakness which, encompasses age-related fragility, in particular osteoporosis". Osteoporosis mainly affects women, but can also affect men. In her book "Women's Health and Fitness Guide" Michelle Kettles and her co-authors state that after the age of 65, women are more likely to be affected by frailty than men. According to the National Institutes of Health, about 50 percent of women and 25 percent of all men older than 50, will break a bone due to osteoporosis. Elderly women outnumber elderly men, making frailty an important issue for women.
According to a new study published in the Journal of Clinical Endocrinology & Metabolism (JCEM), an optimal range of blood levels of Vitamin D, between 20.0 and 29.9 nanograms per milliliter (ng/ml), is considered to be the lowest risk of frailty in the elderly. Levels that are higher or lower than the optimal range are more likely to be associated with frailty in older women.1
The new study which was conducted at the University of Minnesota with 4,551 women participants aged 69 years and above, supports the need for adequate levels of Vitamin D. In addition to the relationship between Vitamin D and frailty, the study observed that women with lower Vitamin D levels (below 20 ng/mL) at the outset of the study were linked to an increased risk of frailty or death after 4.5 years of study.
None of the women were considered to be frail when the study commenced. Out of the 4,551 women, 16 percent became frail and about 10 percent died over the follow-up period. The risk of becoming frail or dying was seen to be 21 percent higher among women who had low levels of Vitamin D at the outset as compared to those who had optimal levels of Vitamin D. Women who started the study with higher levels of Vitamin (higher than 30 ng/ml) did not show an increased or decreased risk of frailty. These results are consistent with other observational studies that imply that a blood level between 20 and 30 ng/ml may help prevent frailty in the elderly.
In an accompanying editorial in the same journal, Clifford Rosen, MD, and JoAnn Manson, MD, DrPH, from the Maine Medical Center Research Institute and Brigham and Women's Hospital, and Harvard Medical School said, "In the meantime, the [new] paper reminds us that maintenance of adequate serum 25OHD levels in our elderly population is clinically important and that, based on existing evidence, vitamin D supplementation should be targeted to reach levels (i.e. 20-29 ng/ml) that are safe as well as efficacious." 2
Vitamin D deficiency
In the body, Vitamin D is found in two forms: Vitamin D3 (cholecalciferol) and D2 (ergocalciferol). Vitamins D3 and D2 are hydroxylated in the liver and kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.
A lack of Vitamin D in adults has been associated with osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases. Some studies shows that Vitamin D may help minimize the incidence of various types of cancer and type-1 diabetes.3
Other studies have also linked Vitamin D deficiency with muscle weakness and slowed movement. A study published in the Journal of Clinical Endocrinology and Metabolism was the first to establish a clear link between Vitamin D levels and accumulation of fat in muscle tissue which leads to lower muscle strength.4 In a related study, Dr. Heike A. Bischoff-Ferrari, a research scientist at the Center for Aging and Mobility at the University of Zurich, Switzerland analyzed eight trials associating Vitamin D with the prevention of falls in the elderly. Dr. Heike and her team found that Vitamin D supplements reduced the risk of falling by 19 percent over one to three years. The dosage of Vitamin D used in these trials ranged between 700 and 1,000 IU.5
Vitamin D dosage
Dr. Kristine Ensrud, who led the study at the University of Minnesota, suggests that the elderly women follow the Institute of Medicine's (IOM) Recommended Dietary Intake (RDI) of 800 IU per day for adults in their 70s and up. For everyone else older than 12 months the RDI is 600 IU per day.
Vitamin D supplements may be used to ensure adequate levels of Vitamin D intake. However, the IOM suggests that the daily dosage of Vitamin D not exceed 4,000 IUs.
Manufacture Your Own Vitamin D supplements
Vitamin D can be used as fortification in many products. It is popularly consumed as dietary supplements in the form of tablets, capsules, powders, gummies, liquids and chewables.
1. "Circulating 25-Hydroxyvitamin D Levels and Frailty Status in Older Women"Journal of Clinical Endocrinology & Metabolism, December 2010, Volume 95, Pages 5266-5273, doi:10.1210/jc.2010-2317.
2. Editorial: "Frailty: A D-Ficiency Syndrome of Aging?", Journal of Clinical Endocrinology & Metabolism, December 2010, Volume 95, Pages 5210-5212.
3. Vitamin D, Medine Plus, National Institutes of Health, nlm.nih.gov/medlineplus/druginfo/natural/929.html
4. Journal of Clinical Endocrinology and Metabolism (doi:10.1210/jc.2009-2309).
5. Effect of vitamin D on falls: A meta-analysis. Journal of the American Medical Association. 2004;291(16):1999-2006.