Why Vitamin D Supplements May Not Work If Your Kidneys Aren’t Healthy, Doctors Explain

Doctors explain why vitamin D supplements may not work properly if your kidneys are unhealthy, and how kidney function affects vitamin D absorption.

Vitamin D is commonly referred to as the "sunshine vitamin." This is because, Vitamin D is very important because it helps in keeping your bones healthy and your immune system robust. Moreover, Vitamin D regulates your muscle and even affects your mental health to some extent. Vitamin D supplements are taken by people in India regularly. One very important point that is usually ignored is that for Vitamin D to work properly, your kidneys should be in good health.

In many instances, individuals still experience fatigue, bone pains, or frequent bone fractures even after taking Vitamin D supplements in the form of tablets for several months. In many of such instances, the link that is being overlooked is kidneys.

Process of Vitamin D in Your Body

According to Dr Basavaraj S Kumbar, Consultant- Internal medicine, Aster Whitefield Hospital, "When Vitamin D is taken by the body, in the form of sunlight exposure or vitamin supplementation, it does not go to work immediately. Two main activation processes take place. The first occurs in the body's liver, where Vitamin D is converted to 25-hydroxyvitamin D, which can then be analysed in the blood screening tests."

"The second, and even more crucial, process occurs in the body's kidneys. The inactive compound at this point is transformed into calcitriol, which becomes fully active to facilitate the body's absorption of calcium in the intestinal tract and its subsequent deposition in bone matrices," he added.

When kidneys are weakening, deteriorating, or ageing, the above process becomes extremely slow. This leads to Vitamin D being inactive in the body and its failure to render its actual benefits.

Why Kidney Health Specifically Relates to Bone Strength?

Active Vitamin D is required for calcium absorption. The deficiency of kidney function translates to the reduced production of active Vitamin D. There is a resulting decrease in the amount of calcium absorbed in the intestines. The parathyroid gland overproduces parathyroid hormone in response. This condition is termed secondary hyperparathyroidism. It increases the amount of calcium in the bloodstream by shifting it from the bones.

With the passing of time, the condition results in weak bones, especially osteoporosis, bone aches, muscular cramps, and an increased risk of breaking down, even if the blood test indicates normal Vitamin D.

Who Is Most at Risk of Vitamin D Not Working?

It's imperative to consider that everyone'sDiabetics, people suffering from hypertension, frequent renal stone disease, those taking pain medication, and those older than 60 years are prone to the reduced functioning of the kidneys. Most of these individuals take Vitamin D for fatigue and/or bone weakness, and the reason these medications don't work may be the inability of the kidneys to activate Vitamin D.

The patients with early-stage kidney disease do not show any symptoms, making it an even more dangerous situation. The patients go ahead with Vitamin D intake, thinking that they are taking care of their bone health, while their Vitamin D level is low at a cellular level.

Hidden Dangers of Blind Supplementation

The doctor explains that another area not considered in this context is the effect that high levels of Vitamin D can have on people suffering from kidney problems, increasing their calcium and phosphate levels in the bloodstream. This can cause an increase in the calcification of people's arteries, heart valves, as well as their kidney tissues, raising the risk of cardiac and kidney problems. This explains why nausea, constipation, kidney stones, or arrhythmias have been known to occur in some patients following high doses of Vitamin D injection or weekly tablets.

What Needs to be Checked Before Taking Vitamin D?

Prior to beginning a course of long-term Vitamin D supplements, kidney function can be checked by simple blood tests, including creatinine and estimated glomerular filtration rate. Blood levels of calcium and phosphate can also be checked from time to time, especially if the patient has diabetes, hypertension, or a family history of kidney problems. Patients who suffer from kidney conditions can also be prescribed the activated form of vitamin D, and not the usual vitamin D supplements, to ensure that they get what their bodies actually need.

Vitamin D is not a one-stop remedy for one's bones and muscles. It is very dependent on one's kidneys. Ironically, one's kidneys are also the main organs responsible for making it active. If one has weak kidneys, then Vitamin D is just a locked bottle of medicine existing but is useless.