Vitamin D After 35: Who Really Needs a Supplement?

Vitamin D supports bone health, muscle function and calcium absorption. But does every man over 35 need a supplement? Discover what the research says about daily requirements, deficiency risks, testing and responsible supplementation.

Key Benefits

• Understand the role of vitamin D in bone and muscle health. • Learn who may be at greater risk of deficiency. • Understand when vitamin D testing may be appropriate. • Avoid unnecessary high-dose supplementation.

𝗧𝗛𝗘 𝗩𝗜𝗧𝗔𝗠𝗜𝗡 𝗧𝗛𝗔𝗧 𝗗𝗢𝗘𝗦𝗡'𝗧 𝗡𝗘𝗘𝗗 𝗛𝗬𝗣𝗘

Vitamin D is often promoted as a solution for everything from low energy and weak immunity to ageing and poor testosterone.

The reality is more specific.

Vitamin D is essential for normal calcium absorption, bone mineralisation and muscle function. Severe deficiency can cause bone problems, including osteomalacia in adults.

But having an adequate vitamin D level does not mean that taking additional high-dose supplements will automatically improve energy, testosterone, immunity or longevity.

For men over 35, the important question is not simply whether vitamin D is useful. It is whether your body is getting enough.

𝗪𝗛𝗔𝗧 𝗩𝗜𝗧𝗔𝗠𝗜𝗡 𝗗 𝗔𝗖𝗧𝗨𝗔𝗟𝗟𝗬 𝗗𝗢𝗘𝗦

Vitamin D helps your body absorb calcium and phosphorus from the digestive system.

These minerals are essential for maintaining healthy bones and supporting normal muscle function.

When vitamin D levels become severely low, the body may struggle to maintain normal bone mineralisation.

In adults, prolonged severe deficiency can lead to osteomalacia, a condition that causes soft, weakened bones and may produce bone pain and muscle weakness.

This is why vitamin D matters. But its biological importance should not be confused with proof that extra supplementation prevents every chronic disease.

𝗪𝗛𝗢 𝗠𝗔𝗬 𝗕𝗘 𝗔𝗧 𝗥𝗜𝗦𝗞 𝗢𝗙 𝗟𝗢𝗪 𝗩𝗜𝗧𝗔𝗠𝗜𝗡 𝗗?

Some men are more likely than others to have inadequate vitamin D levels.

Potential risk factors include:

• Limited exposure to sunlight. • Spending most of the day indoors. • Consistently covering most of the skin outdoors. • Darker skin pigmentation, which can reduce vitamin D production from sunlight. • Conditions that affect fat absorption, including certain intestinal disorders. • Some liver and kidney conditions. • Certain medicines that affect vitamin D metabolism.

Living in a sunny country does not guarantee adequate vitamin D levels. Lifestyle, clothing, skin pigmentation, diet and health conditions all influence vitamin D status.

𝗛𝗢𝗪 𝗠𝗨𝗖𝗛 𝗗𝗢 𝗬𝗢𝗨 𝗡𝗘𝗘𝗗?

The US National Academies' recommended daily allowances are:

• Adults aged 19–70: 600 IU (15 micrograms) daily. • Adults older than 70: 800 IU (20 micrograms) daily.

These figures refer to total intake from food and supplements, not a requirement to take that amount as a supplement.

The amount an individual needs can differ depending on deficiency, health conditions and clinical circumstances.

𝗗𝗢 𝗬𝗢𝗨 𝗡𝗘𝗘𝗗 𝗔 𝗕𝗟𝗢𝗢𝗗 𝗧𝗘𝗦𝗧?

A blood test measuring 25-hydroxyvitamin D [25(OH)D] is the standard test used to assess vitamin D status.

However, routine testing is not recommended for every healthy adult.

The Endocrine Society's 2024 clinical practice guideline suggests against routine vitamin D testing in generally healthy adults without an established reason for testing.

Testing may be appropriate when a healthcare professional suspects deficiency or when certain medical conditions, symptoms or risk factors justify investigation.

The key distinction is simple: testing should answer a clinical question, not become an automatic annual screening habit.

𝗗𝗢 𝗬𝗢𝗨 𝗡𝗘𝗘𝗗 𝗔 𝗦𝗨𝗣𝗣𝗟𝗘𝗠𝗘𝗡𝗧?

Not every man over 35 needs an additional vitamin D supplement.

The Endocrine Society's 2024 guideline suggests that generally healthy adults under 75 should not routinely take vitamin D doses above the recommended dietary intake solely to prevent disease.

That does not mean supplementation is unnecessary for everyone.

Men with confirmed deficiency, inadequate intake or medical conditions affecting vitamin D absorption or metabolism may need supplementation under professional guidance.

𝗙𝗢𝗢𝗗 𝗦𝗢𝗨𝗥𝗖𝗘𝗦 𝗠𝗔𝗧𝗧𝗘𝗥

Vitamin D can be obtained from several foods:

• Fatty fish such as salmon and sardines. • Egg yolks. • Fortified milk and dairy alternatives. • Fortified breakfast cereals. • Some UV-exposed mushrooms.

Food choices can help support intake, although diet alone may not meet the needs of everyone.

𝗗𝗢𝗡'𝗧 𝗔𝗦𝗦𝗨𝗠𝗘 𝗠𝗢𝗥𝗘 𝗜𝗦 𝗕𝗘𝗧𝗧𝗘𝗥

Vitamin D is fat-soluble, meaning it can accumulate in the body.

Excessive supplement intake can cause vitamin D toxicity, leading to high blood calcium levels. Serious cases can damage the kidneys and cause other complications.

Avoid routinely taking high-dose vitamin D products without a clear medical reason.

𝗠𝗘𝗡𝟯𝟱 𝗧𝗔𝗞𝗘𝗔𝗪𝗔𝗬

Vitamin D is essential, but supplementation should be based on dietary intake, risk factors and medical needs—not marketing claims.

Eat vitamin D-containing foods, discuss testing when clinically appropriate and avoid high-dose supplements without professional guidance.

𝗕𝗢𝗧𝗧𝗢𝗠 𝗟𝗜𝗡𝗘

Vitamin D supports strong bones and normal muscle function. But more is not automatically better. For men over 35, understanding personal risk and maintaining adequate intake is more sensible than taking high doses in the hope of reversing ageing or preventing every disease.