Vitamin D in the Elderly

Written by Karina Chou, dietetic student at University of California, Berkeley.

Reviewed/edited by Katie Dodd, MS, RDN, CSG, LD, FAND

Needs for vitamin D in the elderly increases with advancing age. Vitamin D is often known as the sunshine vitamin. The only nutrient our body can make when exposed to sunlight. However, as many people age, the amount of sun exposure usually decreases over time.

Chronically ill elders may be confined to nursing homes or are just spending less time outdoors. This lack of sun exposure and other factors increases their risk of a vitamin D deficiency.

Vitamin D deficiency can cause all kinds of problems including cognitive impairment, osteomalacia, osteoporosis, fatigue, and mood changes.

It is important to understand how much vitamin D is needed in the elderly, which foods are high in vitamin D, and what the symptoms of vitamin D deficiency are in order to optimize health in the elderly.

Introduction to Vitamin D

Vitamin D is a fat-soluble vitamin that is essential for building and maintaining strong bones. It can even help with calcium absorption. Oftentimes, vitamin D is obtained through sunlight or supplements. Vitamin D can also be taken in through food, though few foods have naturally-present vitamin D.

Why is Vitamin D Important?

Vitamin D helps with a variety of bodily functions. It helps fight infectious, aids in muscle movement, nerve function, cell growth, and reduces inflammation (1).

Vitamin D also promotes the absorption of calcium which is important for bone health. When there is enough calcium absorbed in the body, the bones can mineralize (get strong) rather than become thin or brittle (2).

Vitamin D is also suspected to play a role in prevention and treatment of autoimmune disease, chronic pain, and depression. Though, at this time there is no definitive proof of results through clinical trials. The Institute of Medicine states that by itself, vitamin D, has few wide-ranging health benefits (3).

However, in combination with other supplements, like calcium and phosphorus, vitamin D can maintain normal immune system functions and reduce the risk of bone- and muscle-related illnesses, like osteoporosis, multiple sclerosis, and osteomalacia in older adults. Without vitamin D, the body only absorbs 10-15% of calcium and 60% of phosphorus (8).

While there is still a lot we don’t know, science will continue to provide answers. In the meantime, we do know enough that this is an important nutrient for the elderly.

How Much Vitamin D do the Elderly Need?

How Much Vitamin D Do the Elderly NeedThe need for vitamin D increases with age. Adults age 70 years and younger need 600 IU of vitamin D per day. Adults older than age 70 need 800 IU of vitamin D per day (2).

More specific recommendations on how much vitamin D an individual needs is based on blood work. A vitamin D blood serum concentration tells us how much vitamin D in present in the blood at the time it is tested.

The Endocrine Society recommends a blood serum concentration of vitamin D >30 ng/ml. Those with a low serum vitamin D may need a dose of at least 1,200-1,500 IU of vitamin D supplements daily to increase serum vitamin D to optimal levels (2).

The amount vitamin D someone needs may be affected by many different factors. Talk to your doctor to determine what your individual vitamin D needs are based on your labs and medical conditions. Some deficiencies require higher vitamin D doses (4).

Vitamin D Deficiency

Since vitamin D can be obtained through so many ways, there are also many factors that affect the risk of a deficiency (5):

  • The amount of pollution in an area — pollution can block UVB rays and sun exposure
  • Amount of time spent indoors
  • Skin melanin content — the more melanin in the skin, the less vitamin D the skin can absorb
  • Sunscreen use
  • Amount of clothes protecting skin
  • Advancing age

Since these various outdoor factors can fluctuate and lead to a vitamin D deficiency, it’s important to obtain vitamin D from food and supplements if needed. If you suspect a deficiency, your doctor can perform a blood test as needed.

Symptoms of Vitamin D Deficiency

Symptoms of vitamin D deficiency may include muscle weakness, changes in mood and cognitive function, fatigue, and stress fractures. Weakened muscles and bones from low vitamin D can increase the risk of falls and fractures, which can be fatal for the elderly.

Since vitamin D regulates immune function and the release of neurotransmitters in the brain, like serotonin and dopamine, its deficiency can also cause changes in mood and cognitive function (6).

Long-term effects of vitamin D deficiency include osteoporosis and osteomalacia. Osteoporosis occurs when the body loses too much bone or makes too little bone. The bones become weak and are more likely to break during a fall, or even minor bumps in extreme cases.

Although a lack of calcium plays the main role in the development of osteoporosis, vitamin D works in conjunction with calcium and can help reduce the risk of developing the disease.

On the other hand, osteomalacia is the softening of the bones, and it is the result of a severe vitamin D deficiency. This can lead to fractures or joint pain if left untreated.

Vitamin D Lab Values

 A vitamin D deficiency is typically detected by a serum blood test as discussed above. A medical provider can order this test, known as 25-hydroxyvitamin D (25-OHD), to check for vitamin D deficiency.

There is no established 25-OHD cut-off point or lab value that indicates a deficiency of vitamin D, so interpreting results can vary between physician and labs. And as mentioned, The Endocrine Society recommends a blood serum concentration of vitamin D >30 ng/ml.

Food Sources of Vitamin D

Most people only get 10% of the recommended intake for vitamin D from foods, mainly because very few foods contain vitamin D naturally. In the 1930s, vitamin D deficiency used to be so common in children that it caused rickets, which is the softening or weakening of bones in children. As a result, companies had to fortify food products in order to decrease the number of cases.

By incorporating these fortified foods into your diet, you can increase vitamin D intake.

Natural Food Sources

Natural food sources of vitamin D include salmon, sardines, and shrimp (5). Fatty fish skin from cod, tuna, and mackerel, or fish liver have the highest amounts of natural vitamin D. Smaller amounts are in beef liver, egg yolks, and mushrooms.

Natural Food Sources of Vitamin D

Fortified Food Sources

Americans get most of their vitamin D from fortified foods, largely because of the improvement to food products after high numbers of rickets cases in the past.

Fortified food sources of vitamin D include milk, cereal, yogurt, orange juice, and tofu (5). In the United States, milk is fortified with 100 IU of vitamin D per cup, whereas in Canada, it is fortified by 35-40 IU per 100 mL of milk (2).

Although milk itself is fortified, other dairy products like cheese and ice cream are usually unfortified. Plant-based milks, like soy, almond, or oat milk, are usually fortified with the same 100 IU found in cow’s milk, but it is best to check the Nutrition Facts label for exact numbers.

Fortified Food Sources of Vitamin D

Sunshine Vitamin

Vitamin D is a family of compounds that includes vitamin D1, D2, and D3. Vitamin D is also known as the “sunshine vitamin” because vitamin D3 can be produced on your skin when you are exposed to sunlight.

If you have lighter skin, even standing outside for 15 minutes can be enough for your body to produce all the vitamin D it needs for the rest of the day. Individuals with more melanin in their skin may need a couple hours per day in the sun to produce the same amount of vitamin D (7).

Of course, the amount of skin that is exposed during this time, as well as health and living conditions, also factor into how much vitamin D is produced.

This is part of the reason why vitamin D deficiency is prevalent in elders — the less sun exposure they have, the less vitamin D they produced.

How Does Sunshine Create Vitamin D?

Ever wonder how sunshine creates vitamin D? It’s pretty science heavy, but here’s the scoop. When ultraviolet, UVB, rays from the sun hit our skin, skin tissue starts making vitamin D3. This vitamin D3 is combined into chylomicrons, which are fat cells attached to proteins.

These chylomicrons are then absorbed into our blood and travel throughout the body. The vitamin D that is consumed or made by the skin must be transformed in the liver into a form of vitamin D called vitamin D-25-hydroxylase, and then into another form called 25-hydroxyvitamin D (25-OHD).

This 25-OHD form is finally turned into an active form of vitamin D that will increase calcium absorption (8). Whew, it’s quite the journey. And pretty amazing how the body works.

Things that Impact Vitamin D Absorption

Things That Impact Vitamin D in the elderlyFactors like limited sun exposure, age, melanin levels, fat malabsorption, and obesity can impact vitamin D absorption. When there is limited sun exposure, there is already a significant decrease in the levels of vitamin D obtained.

As individuals age, the risk of vitamin D deficiency increases. Not only due to decreased sun exposure, but also because the skin cannot make vitamin D as efficiently as before.

Individuals with more melanin in their skin, or darker skin, absorb much less vitamin D, thus requiring more sun exposure to produce the same vitamin D as an individual with lighter skin. The greater amount of melanin also lowers the skin’s ability to produce vitamin D, but this can be balanced out with supplements or dietary intake.

Vitamin D is a fat-soluble vitamin, so it requires fat in the gut to be absorbed completely. If an individual cannot absorb fat as efficiently, they also may need to use supplements to obtain the recommended levels of vitamin D.

Vitamin D Supplements

It can be difficult to get enough vitamin D through sun exposure and food alone based on the various factors of vitamin D intake involved, so some individuals may take supplements to reach the recommended levels of vitamin D.

Popular brands include Life Extension, Nutrigold, Nature’s Way, and NOW Foods. Supplements, either in tablet or liquid form can provide both D3 and D2 forms.

Vitamin D3, also known as cholecalciferol, is the preferred form of supplementation. And vitamin D2, also known as ergocalciferol, is plant-derived, so it can be especially helpful for vegans or vegetarians.

Vitamin D2

Vitamin D2 is less potent and works for a shorter amount of time compared to D3. It This form is produced by plants when the UV lights hit their leaves.

Some foods with vitamin D2 include mushroom, fortified foods, and dietary supplements. D2 is less expensive to produce, so many of the fortified foods you can find in your grocery store mostly have vitamin D2.

Vitamin D3

Vitamin D3Vitamin D3 is produced by the skin through UV rays, and it is mostly produced by animal sources. It can also be up to twice as effective as vitamin D2.

Some examples of foods with vitamin D3 include oily fish or fish oil, liver, egg yolks, butter, and some dietary supplements.

Liquid Vitamin D

Many vitamins and supplements are also available in a liquid form. This can be especially helpful for individuals who have difficulties swallowing large pills. Liquid vitamin D can also be added to beverages without altering the taste of the original drink.

Although vitamin D is fat-soluble, some liquid vitamin D supplements are water-based, so it may be easier to digest, especially for those who have digestion issues from any surgeries.

Liquid supplements also don’t have as many binders or fillers like in oral tablets, so some may consider it to be much more natural, and it’s much easier to modify the dosage levels.

However, taking liquid vitamin D also comes with risks. It can be dangerous if you don’t use the correct amount of liquid vitamin D drops. Overdosing can result in nausea, decreased appetite, or constipation.

Some brands also require refrigeration, which can make it a hassle to carry around. Liquid supplements are also less stable, so it may not be as effective over a long period of time (9).


Vitamin D is important in creating a healthy immune system and strong bones in all individuals. However, it is especially important that elders obtain enough vitamin D due to the increased risks of fatal fractures or falls, osteoporosis, and osteomalacia associated with a vitamin D deficiency.

Sun exposure is effective in helping the body produce vitamin D3. However, vitamin D can also be consumed through fatty fish or fortified foods like milk, cereal, and yogurt.

Individuals who have difficulty with fat malabsorption, have darker skin, or live in highly polluted areas may find it beneficial to supplement their diet with liquid or tablet forms of vitamin D in order to prevent vitamin D deficiency.

Vitamin D in the Elderly Infographic



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  • Cooperman, Tod. “Are Liquid Vitamins Better than Pills?” com, 23 June 2018,

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