Does Too Much of the B Vitamins Affect Your Kidneys?

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The B vitamins are a group of eight related nutrients your body needs to support a variety of basic functions. Overconsumption of these nutrients can cause a number of problems, but does not have an effect on your kidneys. However, underconsumption of vitamin B-6 can potentially contribute to the development of kidney stones.

B Vitamin Basics

In addition to B-6 — also known as pyridoxamine, pyridoxine or pyridoxal — the B vitamin family includes B-1, also called thiamine; B-2, also called riboflavin; niacin, also called nicotinic acid or nicotinamide; folacin, also called folic acid; vitamin B-12; pantothenic acid; and biotin. You rely on these vitamins for release of the energy contained in food, red blood cell formation, hormone production, nervous system maintenance and formation of your genetic material. Your body also uses various B vitamins for the maintenance of skin health and the prevention of birth defects in the brain and spine.

Excessive Intake Symptoms

All B vitamins belong to a class of substances called water-soluble vitamins. When you consume these vitamins, your body takes what it needs in the short term and passes the rest to your kidneys for elimination in your urine. For this reason, overconsumption risks related to B vitamins are relatively low, according to the American Cancer Society. Still, potential side effects of excessive vitamin B intake include skin problems, abnormally high blood glucose levels, gout and heart problems.

Excessive intake of niacin can lead to nausea, irritability, cramps, blurred vision, worsening of existing ulcers and liver damage or malfunction. Excessive intake of folic acid can interfere with certain chemotherapy medications or hide the effects of a vitamin B-12 deficiency.

Kidney Stones

In addition to kidney stones, Colorado State University Extension lists potential signs and symptoms of a B-6 deficiency that include nausea, irritability, the development of cracks at the corners of your mouth, dermatitis and other skin disorders, an abnormally smooth tongue and the red blood cell disorder called anemia. If you have a genetic disorder called type 1 primary hyperoxaluria, use of B-6 supplements — either on their own or in combination with the mineral magnesium — can potentially lower your risk for the development of kidney stones, MedlinePlus reports.


If your diet includes grain and five daily servings of fruits and vegetables, you probably get enough B vitamins to support your health, the American Cancer Society notes. However, many adults don't eat enough of these or other foods to reach recommended levels of vitamin B intake. Chances of deficiency increase with age, and the National Academy of Sciences recommends all adults past the age of 50 consume vitamin B-enriched foods or take vitamin B supplements. Ask your doctor for more information on the potential effects of vitamin B overconsumption and underconsumption.

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