How Vitamin D Levels Impact Kidney Disease

Sep 22, 2021 | Kidney Disease, Nutrition, Vitamins


  • Vitamin D deficiency is common. It is a fat-soluble vitamin/sunshine vitamin, so you need to monitor levels with supplementation.
  • Vitamin D is activated in the kidneys so patients with kidney disease are more prone to bone disease, cardiovascular disease, autoimmune disease, malignancies, insulin resistance and sarcopenia.
  • The best way to supplement is to take a high-quality D3 with a K2 supplement – make sure to avoid additives, preferably reconstituted in MCT oil to improve bioavailability.

What is Vitamin D

Vitamin D, also known as the sunshine vitamin, is a fat-soluble vitamin that is essential for life and vital to maintain calcium balance, bone health. Low vitamin D levels are associated with the worsening of various diseases such as bone disease, cardiovascular disease, autoimmune disorders, malignancies, musculoskeletal weakness, low muscle mass, insulin resistance(2,3,4,5). Studies confirm that the prevalence of 25(OH) vitamin D deficiency is greater in individuals with CKD than in the general population.(6,7)

Vitamin D receptors are present throughout the body. Vitamin D is produced from cholesterol in the skin with sun exposure but this differs quite a bit depending on your geographic location, sun exposure, skin color, genetic and ethnic factors.

Most people are deficient in vitamin D and so will need supplementation. There are two kinds of vitamin D supplements available, D2(Ergocalciferol) which is from a plant source and D3(Cholecalciferol) which is from an animal source. These are the storage forms of Vitamin D. This gets converted to an active form of vitamin D which is 1,25 dihydroxy vitamin D in the kidney. It is very important to get your vitamin D levels checked regularly along with calcium and parathyroid levels especially in patients with kidney disease. We want vitamin D levels to be at least above 30 ng/dl but the optimal level would be 50-75 ng/dl based on your medical conditions. As it is a fat-soluble vitamin there is a risk of accumulation and toxicity and so needs to be monitored at regular intervals.

Food with natural vitamin D includes wild salmon, cod liver oil, tuna, sardines and mushrooms. Beverages like milk and juices are fortified with vitamin D however the benefit is low given the associated consumption of sugars in these beverages making it more of a marketing strategy rather than a benefit. So if your vitamin D levels are low, make sure to supplement with a good quality supplement without added chemicals and additives. It is better to take vitamin D with K2 as it helps mobilize the calcium into the bones and prevents soft tissue calcification.

Table 1(1)

Vitamin D & Chronic Kidney Disease (CKD)

CKD is associated with imbalances in electrolytes, as the kidney function goes down, phosphorus levels rise, calcium levels decrease, parathyroid levels increase. Calcium levels are tightly regulated in the body and active vitamin D and parathyroid hormones are crucial to maintaining this. As the kidney function decreases active vitamin D levels decrease and so in CKD repletion of active vitamin D is necessary. So it is important to check calcium, magnesium, phosphorus, parathyroid hormone, vitamin D levels in patients with CKD.


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Dr. Nandana Mapakshi is a medical doctor, nephrologist, and functional medicine practitioner. She founded Functional Kidney Care to help her optimize patients’ kidney health and overall wellness using a personalized, comprehensive approach powered by the principles of functional medicine, which treats the whole person, not just symptoms. 

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