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Vitamin C -

If you are a lover of citrus fruits, then we recommend that you keep your consumption in check, because vitamin C can cause irreparable damage to your body if you take too much of it. Although vitamin C is water-soluble, excessive intake can cause gastrointestinal issues such as diarrhea, nausea, and abdominal cramps.

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Vitamin C -

Megadosing with vitamin C supplements can also increase your risk of developing kidney stones, especially if you lead a sedentary lifestyle. As mentioned, vitamin C is quite abundant in citrus fruits (like oranges and lemons), but it can also be found in strawberries, kiwi, bell peppers, broccoli, and tomatoes, for instance.

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Vitamin B1 -

Vitamin B1 is also known as thiamine, and it is essential for energy metabolism and nerve function. Thankfully, excessive intake of B1 is relatively uncommon and doesn’t typically have significant adverse effects. However, megadoses of thiamine supplements may cause an upset stomach, itching, and even skin rashes.

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Vitamin B1 -

Thiamine is found in foods such as whole grains, pork, beef, nuts, seeds, legumes, and fortified cereals. Interestingly, B1 can also be taken via repeated injections, which is only recommended at the behest of a medical professional, as it could cause severe allergic reactions.

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Vitamin B2 -

Also known as riboflavin, vitamin B2 is necessary for producing energy in the human body and for normal cellular function. Much like thiamine, excessive intake of riboflavin is generally rare and negative side effects are not often reported. High doses of B2 supplements can sometimes cause bright yellow discoloration of urine, but this is harmless.

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Vitamin B2 - Synthetic riboflavin is often prescribed by ophthalmologists to treat eye disorders, but more natural food sources of the vitamin include milk and dairy products, eggs, lean meats, and green leafy vegetables.

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Vitamin B3 -

The third vitamin in the B group is also known as niacin or nicotinic acid, and it is one of just a few vitamins also classified as prescription medication. Overconsumption of niacin can lead to niacin toxicity, which is characterized by symptoms like flushing of the skin, itching, nausea, vomiting, abdominal pain, and liver damage.

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Vitamin B3 -

Chronic excessive intake of B3 may also increase the risk of insulin resistance and metabolic syndrome, which could lead to diabetes. Niacin is naturally present in foods like meats (especially liver and poultry), fish (such as tuna and salmon), nuts, and enriched grains.

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Vitamin B5 -

Although vitamin B5 (also called pantothenic acid) is crucial for energy metabolism and creating hormones in the human body, there’s very limited evidence on the adverse effects of excessive intake. However, megadoses of pantothenic acid supplements may cause diarrhea, nausea, and stomach cramps.

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Vitamin B5 -

High-dose supplements of vitamin B5 are sometimes used to treat high blood levels in cholesterol patients, which reduces the risk of cardiovascular diseases. More natural food sources of vitamin B5 include meat (especially liver), poultry, fish, eggs, whole grains, and avocados.

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Vitamin B6 -

Vitamin B6 is also known as pyridoxine, and it is a crucial vitamin that helps the nervous system and metabolism function efficiently. But consuming too much B6 can lead to an overload of our nervous system and cause sensory neuropathy, resulting in numbness, tingling sensations, and nerve damage, particularly in the hands and feet.

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Vitamin B6 -

Long-term overconsumption of pyridoxine supplements may also result in nerve toxicity, which is most often irreversible. Food sources of vitamin B6 include poultry (especially chicken and turkey), fish (like tuna and salmon), potatoes, bananas, and chickpeas.

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Vitamin B7 -

Vitamin B7 (also called biotin) is another vitamin that doesn’t often result in any major adverse effects. B7 is essential for metabolism and maintaining healthy hair, skin, and nails, but extremely high doses of biotin supplements may interfere with certain laboratory tests, leading to inaccurate results.

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Vitamin B7 -

Biotin overdose can also include insomnia and dehydration, but these symptoms are quite rare. Foods such as eggs, liver, nuts, seeds, and sweet potatoes usually contain this vitamin.

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Vitamin B9 -

Here is another vitamin from the B class that can cause negative effects when consumed in excess. Also known as folate, vitamin B9 is essential for cell division and the synthesis of DNA. Interestingly, excessive intake of folate supplements can mask vitamin B12 deficiency symptoms and interfere with certain medications.

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Vitamin B9 -

High doses of B9 supplements may also increase the risk of colorectal cancer in some individuals. Folate is naturally found in foods like leafy greens (such as spinach and kale), legumes (lentils and chickpeas), fortified grains, and citrus fruits.

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Vitamin B12 -

Much like B9, vitamin B12 is a crucial factor for nerve function and DNA synthesis, although excessive intake is generally well-tolerated. Indeed, excess amounts are usually excreted in the urine without any adverse effects. However, extremely high doses of vitamin B12 supplements may cause acne-like rashes, itching, and, in rare cases, anaphylaxis.

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Vitamin B12 -

Vitamin B12 is also known as cobalamin, and it is primarily found in animal products such as meat, fish, poultry, eggs, and dairy products. It is one of the three most important vitamins for humans to consume, alongside vitamin D and iron.

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Choline - Choline was once classified as vitamin B4, and it is vital for the function of many different parts of the human body, including brain health, metabolism, and cell structure. Excessive intake of choline, especially through supplements, can lead to low blood pressure, sweating, fishy body odor, and gastrointestinal issues.

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Choline -

Some studies have suggested that there is also a potential link between high choline intake and an increased risk of cardiovascular disease. The vitamin is naturally found in foods like eggs, meat (especially liver), fish, dairy products, and certain vegetables like broccoli and Brussels sprouts.

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Salicylic acid -

Although not commonly referred to as a vitamin, salicylic acid is primarily found in medications like aspirin and certain plants like willow bark. When consumed in excessive amounts, it can lead to aspirin toxicity, causing symptoms such as stomach ulcers, gastrointestinal bleeding, ringing in the ears, and confusion.

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Salicylic acid -

For people with sensitive skin, overconsumption of salicylic acid can drastically dehydrate the skin and cause intense irritation. However, if used in moderation, it can be truly beneficial and help in maintaining skin health.

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Vitamin A -

Consuming excessive amounts of vitamin A, usually in the form of retinol, can lead to a condition called hypervitaminosis A. Symptoms may include nausea, dizziness, blurred vision, bone pain, and, in severe cases, liver damage and birth defects.

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Vitamin A -

Vitamin A is crucial for normal vision, the immune system, and reproduction, as well as maintaining the health of your heart and lungs. Fortified dairy products are common places where vitamin A can be found, alongside eggs and some fruits and vegetables like carrots and spinach.

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Vitamin D -

While vitamin D is essential for bone health and immune function, overconsumption can lead to hypercalcemia, a condition characterized by too much calcium in the blood. This typically results in kidney stones, tissue calcification (especially in blood vessels), nausea, vomiting, weakness, and even heart rhythm abnormalities.

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Vitamin D -

Vitamin D is argued to be the most important vitamin for human life, and it is primarily obtained from sunlight exposure. Other sources include fatty fish and dairy products, but many doctors recommend consuming vitamin D supplements in order to avoid any potential deficiencies.

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Vitamin E -

Vitamin E has been known to be an important antioxidant that has a marked improvement on cardiovascular diseases when taken in moderation. However, high doses of vitamin E supplements can increase the risk of bleeding, particularly in individuals taking blood-thinning medications.

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Vitamin E -

Prolonged consumption of excessive vitamin E may also interfere with the body's ability to form blood clots properly. Foods that are rich in vitamin E include nuts (especially almonds and hazelnuts), seeds (like sunflower seeds), vegetable oils (such as sunflower oil), and green leafy vegetables.

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Vitamin K -

Vitamin K is crucial for blood clotting and bone health in the human body, and consuming too much of it can interfere with these processes of the body. Individuals who overconsume vitamin K while ingesting prescribed anticoagulant medications may find their bodies experiencing bleeding issues.

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Vitamin K -

Thankfully, excessive vitamin K intake is rare through diet alone, as it can only be made by plants. The vitamin is found in leafy green vegetables, broccoli, Brussels sprouts, and vegetable oils (such as soybean and canola oil).

Sources: (Healthline) (Everyday Health) (WebMD) (Better Health Channel) (Elo Health) (Britannica)

See also: These foods work wonders for these parts of your body

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