Vitamin B is used to help maintain proper cell metabolism. It is a water soluble vitamin that the body breaks down through digestion to promote proper bodily function. Originally scientists believed that there was only one B vitamin, but research has shown that there are 8 vitamins in the B vitamin complex: B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pantothenic Acid), B7 (Biotin), B9 (Folic Acid), and B12 (Cyanocobalamin). Each of these vitamins plays a distinct role in maintaining the human body. So many take vitamin B complex supplements to enhance these natural effects. However, vitamin B complex side effects should also be noted.

Side Effects of Vitamin B Complex

Side effects of taking a B vitamin complex are not common, especially if the patient takes the medication as prescribed amount. However, taking excessive amounts of a vitamin B complex can cause side effects. An overdose is signaled by dizziness, frequent urination, change in the color of the urine, black stools, constipation, diarrhea, abdominal pain, nausea, vomiting, redness of the skin and itching.

In severe cases, patients may develop an allergic reaction to their vitamin B complex. If you are taking a B vitamin complex and suddenly experience itching, a rash, kidney stones, swelling, wheezing or hives, stop taking the complex right away. If your symptoms persist or you feel as though your reaction is life threatening, contact your physician as soon as possible.

Side Effects of Vitamin B Complex Components

When you experience vitamin b complex side effects, patients may experience side effects from excessive exposure to a specific B vitamin. In most cases, this discomfort can be eased by limiting your intake of the vitamin. If your reaction is particularly severe, contact your doctor immediately.

Vitamin B1 - Thiamine

In rare cases, a thiamine overdose can cause restlessness, fluid retention, nausea, weakness and sweating. In severe cases, a thiamine overdose can cause dizziness, difficulty breathing, and tightness in the chest, swelling of the tongue or face, or discoloration of the skin. Allergic reactions to thiamine can cause itching, hives or rashes on the skin.

Vitamin B2 - Riboflavin

Taking a riboflavin supplement will frequently cause the urine to turn a yellow-orange color. This side effect is harmless. In higher dosages, riboflavin may result in increase in urination or diarrhea. Severe reactions can cause difficulty breathing, swelling of the face, lips, throat or tongue, or hives on the skin.

Vitamin B3 - Niacin

Niacin will frequently cause flushing, which may include burning, sweating, tingling, redness or chills. These can last as long as 4 hours after taking the supplement, but this is a harmless condition. Other common side effects of taking niacin include upset stomach, nausea, vomiting, diarrhea, heartburn or dizziness. In severe cases, taking niacin can result in persistent headache, irregular heartbeat, swelling of the arms or legs, joint pain, or blurred vision. In rare cases, patients may also experience intense abdominal pain, incessant nausea or vomiting, bloody or black stools, yellowing of the eyes and muscle or joint pain. Allergic reactions to niacin can result in swelling of the lips, tongue, throat or face, itching or hives.

Vitamin B5 - Pantothenic Acid

Patients who take pantothenic acid are very prone to overdose, making patient experience vitamin b complex side effects. This can result in severe diarrhea. In rare cases, patients may develop an allergic reaction which may result in tightness of the chest, trouble breathing or swelling of the face, throat, lips or tongue.

Vitamin B6 - Pyridoxine

Harmless effects of pyridoxine include stomach pain, drowsiness, tingling, and loss of appetite, nausea, or vomiting. Frequently ingesting large doses of pyridoxine can cause brain and nerve problems. In rare cases, this can lead to a numbing sensation in various parts of the body, most notably in the hands and feet, poor coordination or extreme fatigue. Allergic reactions to pyridoxine can result in swelling of the face, tongue, lips or throat, trouble breathing or hives.

Vitamin B9 - Folic Acid

Taking excessive amounts of folic acid can increase the risk of heart attack, particularly in those who already suffer from heart trouble. Overusing folic acid may also increase your risk of developing lung or prostate cancer. Those receiving injections of folic acid may experience pain and swelling or pain near the injection site. In severe cases, allergic reactions may cause swelling of the lips, face or tongue, tightness in the chest, hives, rash or dizziness.

Vitamin B12 - Cyanocobalamin

Patients using cyanocobalamin may experience diarrhea, itching or an increased risk of blood clots. In severe cases, allergic reactions to cyanocobalamin can cause chest pain, swelling of the face, tongue, or lips, swelling of the body, muscle weakness, fever, chills, bruising or bleeding.

Precaution of Vitamin B Intake

You should not take B vitamin supplements if you are breastfeeding, pregnant, suffer from diabetes, ulcers or gout, are prone to allergic reactions to medications or are taking additional herbal or complementary medications that could negatively react to these vitamins. Combine your supplement use with a healthy diet, natural sources of B vitamins, a balanced diet and exercise for the best results to reduce vitamin b complex side effects.