Vitamin D in Older Adults
Let’s talk about vitamin D in older adults. We know that vitamin D is an important nutrient that each and every one of us need on a daily basis. Vitamin D does a lot of important stuff in our bodies from maintaining bone health to immune function to reducing inflammation (1).
In older adults, research suggests that vitamin D can be helpful in both reducing falls and fractures (2). In addition to maintaining bone health, vitamin D may even play a role in the prevention of osteoporosis in older adults (1). This fat-soluble vitamin has many functions and is important for overall well-being.
Even though we all need it, many of us do not get the vitamin D our bodies require. And for older adults, it can be even harder to get the vitamin D they need. Let’s take a look at vitamin D in older adults.
How Much Vitamin D is Needed?
According to the Institute of Medicine (IOM), the Recommended Daily Allowance (RDA) for vitamin D varies by age but is the same for both men and women.
Vitamin D Recommended Daily Allowances:
· Ages 0 - 12 months: 400 IU
· Ages 1 - 70 years: 600 IU
· Ages 70+ years: 800 IU
What do some other organizations recommend when it comes to vitamin D in older adults?
Oregon State University’s Linus Pauling Institute recommends 2,000 IU vitamin D supplementation daily for adults. They emphasize this is most important in the elderly population (2). The Endocrine Society recommends supplementation of 1,500 to 2,000 IU of vitamin D in older adults at risk for vitamin D deficiency to raise serum vitamin D levels to > 30 (3).
Not Enough Vitamin D
Inadequate vitamin D can cause rickets in children, typically identified with the bowing of the legs. In adults, vitamin D deficiency can cause osteomalacia, a softening of the bone that can contribute to pain and increase the risk of osteoporosis. Muscle weakness and pain has also been associated with vitamin D deficiency (2).
Too Much Vitamin D
Like any other nutrient, getting too much vitamin D can be a bad thing. The IOM has set a tolerable upper limit level (UL) for vitamin D at 4,000 IU for adults. However, most reports suggest that the toxic effects of vitamin D do not appear at intakes less than 10,000 IU of vitamin D daily (1,2).
Vitamin D toxicity can lead to damage of the heart, blood vessels, and kidneys. Signs of vitamin D toxicity are often easy to miss because the symptoms are very non-specific – lack of appetite, loss of weight, increased thirst, and heart arrhythmias (1).
Getting enough vitamin D is a balancing act.
Where Does Vitamin D Come From
The vitamin D for humans generally comes from three different sources.
Sources of Vitamin D:
Vitamin D is known as the “sunshine vitamin” because it can be produced in our bodies when sunlight reaches the skin and triggers the synthesis of vitamin D. But getting a little sunshine is not as easy as it sounds. There are many variables that affect how vitamin D is synthesized through the skin.
After sunlight, the next source of vitamin D is food. Unfortunately, we don’t find high levels of vitamin D in a lot of different food sources. Very few foods naturally contain vitamin D and many other foods are supplemented with vitamin D.
Food Sources of Vitamin D (1):
· Cod liver oil
· Fatty fish (like salmon, swordfish, tuna, and sardines)
· Fortified beverages (orange juice and milk)
· Fortified cereals
The final source of vitamin D is through supplementation. Supplementation may be provided through a multivitamin or a single-vitamin supplement. Be sure to read the supplement label for dosing information.
It’s Hard to Get Enough Vitamin D
It’s hard for older adults to get the vitamin D they need. It’s estimated that half of older adults with hip fractures in the United States alone were deficient in vitamin D (1). There are several reasons why older adults have a greater risk for vitamin D deficiency.
As we age our skin is unable to synthesize vitamin D as efficiently as it did in our younger years. Elderly with darker completions may synthesize even less vitamin D. On top of that older adults are more likely to spend more time indoors (1).
Those who do get outside a lot are likely keeping their skin safe by using sunblock or sun protective clothing. Both of these actions, while good for skin health, do minimize the ability to get vitamin D from the sun. And finally, people who live further from the equator also get less vitamin D from the sun (1).
So, getting enough vitamin D through sunlight alone is challenging for the older adult. When sunlight doesn’t work, we look at food. But unfortunately, it can be difficult to get the amount of vitamin D you need from food alone. Especially for the elderly over age 70 years who have higher vitamin D needs.
Above we reviewed how few foods contain vitamin D. Below is an example of what an older adult greater than 70 years of age would have to eat to meet the RDA of 800 IU of vitamin D through food alone:
· 2 eggs (74 IU)
· 4 ounces salmon (620 IU)
· 1 cup fortified cereal (50 IU)
· 1 cup fortified milk (98 IU)
If an older adult ate the foods above, they would have approximately 842 IU of vitamin D. You can see how intentional someone would need to be to meet their vitamin D needs every day. Plus, not everyone likes foods high in vitamin D.
It can be hard to get enough vitamin D.
Vitamin D Supplementation
When someone is unable to get enough vitamin D through sunlight and food alone, the next option is supplementation. Vitamin D supplements come as vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol). Vitamin D3 is recommended as the best option for supplementation of high doses (1).
Vitamin D supplements typically come in 1,000 IU, 2,000 IU, or 5,000 IU increments. Multivitamins also contain some vitamin D3 if you just need a little extra. If an older adult is on an oral nutrition supplement, these are frequently supplemented with vitamin D as well.
Are You Getting Enough?
What is the best way to know if you need more vitamin D? Getting your lab work done – more specifically, your serum 25-hydroxyvitamin D [25(OH)D] concentration levels measured. Serum vitamin D levels are the gold standard for determining vitamin D status.
The IOM has set the following guidelines for serum vitamin D levels (1):
· <30 nmol/L Inadequate
· 30 to <50 nmol/L At risk for inadequacy
· >/= 50 nmol/L Generally considered adequate
Knowing serum vitamin D levels is beneficial in determining if someone is clinically deficient in vitamin D. This can guide interventions from increased food sources to supplementation. Vitamin D should be rechecked to determine if interventions successful in rising serum vitamin D levels.
Emerging Research on Vitamin D
Like most nutrients, new research is constantly emerging on vitamin D. For example, a 2019 an article was published suggesting there is little benefit to taking very high dose vitamin D supplements in older adults (greater than age 70 years) to improve bone mineral density (4).
A rather large systematic review and meta-analysis was published in late 2017 in the Journal of the American Medical Association that raised quite a bit of controversy. This large study found that the use of calcium, vitamin D, or both was not associated with a significant decrease in risk of hip fractures when compared to a placebo or no treatment. Researchers suggested that the routine use of vitamin D in community-dwelling older adults was not warranted (5).
In 2018 other researchers insisted that the research in this meta-analysis had some issues and that it is too early to recommend discontinuing the use of calcium and vitamin D in older adults for the prevention of fractures (6).
Research continues to arise and may change how we view vitamin D in clinical care.
The Bottom Line
The bottom line is that nutrition includes the whole diet and not a single nutrient. Vitamin D is likely not the “super nutrient” to solve all of our problems (despite the way the media may hype it up to be). But, is an important nutrient that plays a vital role in the function of our bodies.
In particular, vitamin D is an important nutrient for older adult. It comes from several different sources, but it still can be hard to get enough every day. Many older adults are deficient in vitamin D. And this is an issue.
So, what should we do? Older adults should be encouraged to consume a balanced diet including foods that provide adequate vitamin D. Older adults may also benefit from the monitoring of serum vitamin D levels to detect deficiency. Appropriate interventions, including supplementation, are needed when deficiency is present.
And maybe encourage a little sunshine for good measure. It’s good for all of us.
RD Nutrition Consultants LLC, is the industry leader in Clinical Dietitian Services Nationwide. We specialize in providing contract Registered Dietitian services in a wide variety of healthcare and wellness organizations.
1. Vitamin D: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed September 29, 2019.
2. Vitamin D. Linus Pauling Institute Micronutrient Information Center website. https://lpi.oregonstate.edu/mic/vitamins/vitamin-D. Updated 2017. Accessed September 30, 2019.
3. Holick M, Binkley N, Bischoff-Ferrari H, et al. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline. J Clinc Endo & Metab. 2011: 90(7):1911-1930.
4. Aspray TJ, Chadwick T, Francis RM, et al. Randomized controlled trial of vitamin D supplementation in older people to optimize bone health. The American journal of clinical nutrition. 2019 Jan 1;109(1):207-17.
5. Zhao JG, Zeng XT, Wang J, Liu L. Association between calcium or vitamin D supplementation and fracture incidence in community-dwelling older adults: a systematic review and meta-analysis. JAMA. 2017 Dec 26;318(24):2466-82.
6. Bischoff-Ferrari HA, Dawson-Hughes B, Willett WC. Issues of trial selection and subgroup considerations in the recent meta-analysis of Zhao and colleagues on fracture reduction by calcium and vitamin D supplementation in community-dwelling older adults. Osteoporosis International. 2018 Sep 1;29(9):2151-2.