Water Soluble-8

What are two key differences between water-soluble and fat-soluble vitamins?

Water-soluble vitamins dissolve in water, enter the bloodstream directly, and most are stored in limited amounts. Fat-soluble vitamins dissolve in fat, are absorbed with dietary fat, and can be stored in the liver and body fat.

What are the main functions of thiamin (B1)?

Thiamin helps enzymes metabolize carbohydrates and produce energy. It also supports normal nerve function.

What are the main functions of riboflavin (B2)?

Riboflavin helps release energy from nutrients and supports normal cell growth and function.

What is FAD, and how is it related to riboflavin?

FAD (flavin adenine dinucleotide) is a coenzyme made from riboflavin. It helps enzymes carry out energy-producing reactions in cells.

What can niacin (B3) deficiency and toxicity cause?

Severe niacin deficiency causes pellagra, characterized by dermatitis, diarrhea, and dementia. High-dose niacin supplements can cause flushing, itching, liver damage, and other side effects.

What are food sources of niacin (B3)?

Meat, poultry, fish, peanuts, whole and enriched grains, and foods containing tryptophan, which the body can convert into niacin.

How can niacin affect cholesterol?

Prescription-strength niacin can lower LDL cholesterol and triglycerides and raise HDL cholesterol, but side effects limit its use. It should not be taken in high doses for cholesterol without medical supervision.

What is pantothenic acid (B5), and what does it do?

Pantothenic acid is part of coenzyme A, which helps the body metabolize carbohydrates, fats, and proteins. It is found in many foods, so deficiency is rare.

What is biotin (B7), and what does it do?

Biotin helps enzymes metabolize carbohydrates, fats, and proteins. It also participates in reactions needed for fatty acid synthesis and glucose production.

What are food sources of biotin (B7)?

Cooked eggs, meat, fish, nuts, seeds, legumes, and some vegetables. Raw egg whites contain avidin, which binds biotin and can reduce absorption if consumed frequently in large amounts.

What are the functions of vitamin B6, and what can toxicity cause?

Vitamin B6 helps metabolize amino acids, make neurotransmitters and hemoglobin, and support immune function. Excessive supplement doses over time can cause nerve damage.

What are food sources of vitamin B6?

Poultry, fish, meat, potatoes, chickpeas, bananas, and fortified cereals.

What are the signs of vitamin B6 deficiency?

Deficiency can cause dermatitis, cracks at the corners of the mouth, anemia, confusion, and impaired immune function.

What are the functions of folate, and what is the recommended amount?

Folate is needed for DNA synthesis, cell division, and red blood cell formation. The adult RDA is 400 micrograms of dietary folate equivalents (DFE) per day; needs increase during pregnancy.

What are food sources of folate?

Dark green leafy vegetables, legumes, citrus fruits, and liver. Folic acid is commonly added to enriched grain products and used in many supplements.

What can excessive folic acid intake cause?

High folic acid intake from supplements or fortified foods can correct the anemia caused by vitamin B12 deficiency while allowing nerve damage to continue undetected.

What are neural tube defects (NTDs)?

Birth defects involving the developing brain or spinal cord, such as spina bifida and anencephaly, that occur early in pregnancy.

How does folic acid help prevent neural tube defects?

Adequate folic acid before conception and during early pregnancy lowers the risk of neural tube defects because it supports normal neural tube development.

Who should take folic acid to help prevent neural tube defects?

People who could become pregnant are advised to consume 400 micrograms of folic acid daily from supplements or fortified foods, in addition to folate from a varied diet, unless a healthcare professional recommends a different amount.

How can vitamin B6 and folate deficiencies cause anemia?

Folate deficiency can impair DNA synthesis and prevent normal red blood cell development. Vitamin B6 deficiency can impair hemoglobin production and cause anemia.

How are vitamin B6 and folate related to homocysteine?

Vitamins B6 and folate help enzymes convert homocysteine into other substances. Low levels of these vitamins can raise homocysteine in the blood.

What makes vitamin B12 unique among water-soluble vitamins?

Vitamin B12 requires intrinsic factor, a protein made in the stomach, for normal absorption in the small intestine. It can be stored in the liver for years, so deficiency may take a long time to appear.

What are the functions and food sources of vitamin B12?

B12 supports nerve function, DNA synthesis, and red blood cell formation. It is found naturally mainly in animal foods such as meat, fish, eggs, and dairy products, and in fortified foods.

What are the signs and causes of vitamin B12 deficiency?

Deficiency can cause megaloblastic anemia, fatigue, numbness or tingling, and neurological problems. Causes include inadequate intake, especially with strict vegan diets without fortified foods or supplements, and poor absorption.

What are the main functions of vitamin C?

Vitamin C supports collagen formation, wound healing, antioxidant protection, immune function, and absorption of non-heme iron from plant foods.

What are food sources of vitamin C?

Citrus fruits, berries, kiwi, peppers, broccoli, tomatoes, and potatoes.

How does vitamin C improve iron absorption?

Vitamin C helps keep non-heme iron from plant foods in a form that is easier for the body to absorb. Eating vitamin C-rich foods with iron-rich plant foods can improve absorption.

What can vitamin C deficiency and excessive intake cause?

Severe deficiency causes scurvy, which can involve bleeding gums, poor wound healing, and weakness. Very high supplemental intakes can cause diarrhea, nausea, and abdominal cramps and may increase kidney-stone risk in susceptible people.

What is the RDA for vitamin C?

For adults, the RDA is 90 milligrams per day for males and 75 milligrams per day for females. People who smoke need an additional 35 milligrams per day.

What is choline, what does it do, and what happens if intake is too low?

Choline is an essential nutrient used to make cell membranes and acetylcholine, a neurotransmitter. It also helps transport fats from the liver. The adult Adequate Intake is 550 milligrams per day for males and 425 milligrams per day for females. Low intake can contribute to liver or muscle damage.