Vitamin D Supplementaion

[NHE]

Why Don’t Vitamin D Supplements Work as Expected?

Vitamin D supplements are extremely popular. Millions swallow little golden pills daily. But why are clinical trials producing such disappointing results?

https://www.peoplespharmacy.com/article ... s-expected

If you are taking big doses of vitamin D in the hopes that it will ward off all sorts of health problems, you may be disappointed. Most research has not demonstrated that taking high doses of vitamin D supplements will improve health. Why not?

How Weight Affects Response to Vitamin D Supplements:

In a large randomized controlled trial of vitamin D supplements, researchers found that heavier participants did not benefit as much as others (JAMA Network Open, Jan. 17, 2023). The VITAL study included more than 16,000 adults who took vitamin D or placebo for two years. Those who were overweight or obese had lower levels of circulating vitamin D when the study started. More importantly, their levels of vitamin D markers did not rise as much when they took the pills.

The researchers suggest that this may help explain why heavy people don’t seem to get protection from vitamin D supplements. Other participants had a lower risk of cancer or diabetes if they took vitamin D.

When normal-weight volunteers took pills providing 2000 IU of vitamin D daily, their vitamin D levels rose significantly. The investigators note that people carrying excess fat do not increase vitamin D blood levels as much after taking supplements.

One possible explanation is that vitamin D is a fat-soluble compound. As a result, the body’s adipose tissue stores it. Consequently, it is less available to other body tissues. As you will read, it plays a critical role in helping them stay healthy.

The Double Life of Vitamin D:

Vitamin D leads a double life. In addition to being a crucial vitamin, it is also a hormone that affects every cell in the body.

For years, health professionals thought that this nutrient was responsible primarily for building strong bones. When there was a deficiency in vitamin D, children developed rickets. In this condition, bones are fragile and can become deformed, resulting in bowed legs and thickened wrists.

Over the last several decades, scientists have discovered that there are vitamin D receptors throughout the body. People who are deficient in vitamin D are more susceptible to a wide range of disorders, from arthritis and heart disease to diabetes and cancer.

Researchers report that when circulating levels of vitamin D are low, people are more susceptible to respiratory infections and more likely to die prematurely (Circulation Journal, April 20, 2017). That research from Japan has since been confirmed in the UK, Norway and elsewhere.

Health Problems Linked to Low Vitamin D Levels:

• Asthma in children

• Autoimmune disorders such as multiple sclerosis

• Cancer

• Cardiovascular disease (heart attacks, etc)

• Cognitive impairment (Alzheimer’s disease, dementia)

• Diabetes

• Erectile dysfunction

• Fractures, osteopenia, osteoporosis

• High blood pressure

• Infections (pneumonia, colds, etc)

• Mental illness (depression, schizophrenia)

• Psoriatic arthritis

Vitamin D Supplements: A Puzzling Paradox

Scientists don’t understand why vitamin D supplements don’t reliably prevent these serious health conditions. Why aren’t vitamin D supplements working as expected?

Vitamin D and the Sun:

For thousands of years, humans got their vitamin D by exposing their skin to the sun. When ultraviolet rays hit the skin, they help form a precursor of the hormone (cholecalciferol). After the skin absorbs this compound, the kidney converts it into the active form of vitamin D.

There is tremendous variability in the amount of vitamin D the skin will make. It depends in part on the intensity of the sun, the time of day and skin type. Your body can make between 10,000 and 25,000 international units of vitamin D in less time than it takes to develop a sunburn. To a large extent, sunscreen may block the natural formation of vitamin D from the sun (PLoS One, Jan. 29, 2016).

The body carefully regulates its production of vitamin D. You can’t overdose on vitamin D through sun exposure (Institute of Medicine, 2011). Moreover, not all the evidence points to sunscreen blocking vitamin D synthesis. One study found that people applying enough sunscreen to prevent sunburn still made vitamin D (British Journal of Dermatology, Nov. 2019).

New technology makes it possible for people to monitor their UV exposure. A pilot study in Brazil found that people using the Sun4Health phone app with a wearable UV detector mostly avoided sunburn (Photochemical & Photobiological Sciences, Nov. 2022). Nevertheless, they increased their blood levels of 25-hydroxyvitamin D.

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