Chapter 10.2

Thiamin

Thiamin is the vitamin part of the coenzyme TPP that assists in energy metabolism, particularly in the conversion of pyruvate to acetyl CoA.

Riboflavin

Riboflavin serves as a coenzyme in energy metabolism, with its active forms being FMN and FAD that accept and donate hydrogens in reactions.

Coenzymes

Coenzymes like TPP and FAD are essential for enzyme function, aiding in the release of energy from carbohydrates, fats, and proteins.

Thiamin Deficiency

Inadequate thiamin intake can lead to beriberi, a disease characterized by muscle weakness (dry beriberi) and cardiovascular issues like edema (wet beriberi).

Riboflavin Deficiency

Lack of riboflavin can cause inflammation of the mouth, skin, eyes, and GI tract, known as ariboflavinosis.

Thiamin Food Sources

Pork and whole-grain products are rich sources of thiamin, essential for energy metabolism and nerve function.

Riboflavin Food Sources

Milk and milk products are significant sources of riboflavin, crucial for energy metabolism and overall health.

Nutrient Density

Nutrient density refers to the amount of a nutrient per 100 kcalories in a food, highlighting the concentration of essential nutrients in a given portion.

Coenzyme Action

Coenzymes enable enzymes to dismantle or synthesize compounds, crucial for various metabolic pathways in the body.

B Vitamins

B vitamins like thiamin and riboflavin play vital roles as coenzymes in energy metabolism, supporting the breakdown and utilization of macronutrients for energy production.

Niacin

Niacin refers to two chemical structures, nicotinic acid and nicotinamide, which are essential for energy metabolism. The body can convert nicotinic acid to nicotinamide, the major form of niacin in the blood.

Niacin Equivalents (NE)

Niacin recommendations are stated in niacin equivalents to account for the conversion of tryptophan to niacin in the body. 1 mg of niacin requires about 60 mg of tryptophan.

Pellagra

Pellagra is the niacin-deficiency disease characterized by "the four Ds" - diarrhea, dermatitis, dementia, and death. It was prevalent in the US South due to a diet lacking niacin and tryptophan.

Niacin Flush

Large doses of nicotinic acid from supplements can cause niacin flush, dilating capillaries and causing a tingling sensation. Nicotinamide does not produce this effect.

Biotin

Biotin plays a crucial role in the TCA cycle, fatty acid synthesis, and amino acid breakdown. It is found in foods and deficiencies are rare.

Pantothenic Acid

Pantothenic acid is part of coenzyme A, essential for lipid synthesis and neurotransmitter production. Deficiencies are rare, and no toxic effects have been reported.

Vitamin B6

Vitamin B6 exists in three forms and is converted to the active coenzyme PLP, involved in over 100 reactions including amino acid metabolism. Deficiencies can lead to neurological issues and abnormal brain function.

Vitamin Bioavailability

The extent to which the body can absorb and utilize vitamins from foods.

Coenzyme PLP

Pyridoxal phosphate, a form of vitamin B6 that participates in various metabolic reactions, especially in amino acid metabolism.

Folate

Also known as folic acid or folacin, it is essential for DNA synthesis, cell growth, and preventing neural tube defects during pregnancy.

Folate Bioavailability

The amount of folate that the body can absorb and use efficiently, influenced by the source of folate (natural or synthetic).

Folate Deficiency

Inadequate folate levels leading to impaired cell division, anemia, and GI tract issues.

Folate Toxicity

Excessive folate intake that can mask vitamin B12 deficiency symptoms and lead to neurological damage.

Vitamin B12

Essential for DNA and RNA synthesis, nerve function, and bone cell activity, closely related to folate in activation and absorption.

Vitamin B12 Absorption

Involves binding with intrinsic factor in the small intestine for absorption into the bloodstream, crucial for preventing deficiencies.

Vitamin B12 Deficiency

Often due to inadequate absorption, common in individuals with atrophic gastritis or lacking intrinsic factor, leading to pernicious anemia.

Intrinsic Factor

A stomach secretion necessary for the absorption of vitamin B12, forming a complex that is recognized by receptors in the small intestine for uptake.

Vitamin B12

A vitamin primarily found in animal-derived foods, essential for healthy cell replication, nerve activity, and activating folate.

Folate Deficiency

Anemia characterized by large, immature red blood cells due to slow DNA synthesis, caused by inactive folate trapped in methyl folate form.

Neurological Symptoms

Devastating symptoms like creeping paralysis and cognitive decline resulting from a vitamin B12 deficiency, affecting nerve fibers and their growth.

Choline

An essential nutrient, not a vitamin, used to make acetylcholine and lecithin, crucial for fetal neurological development and cognition in adults.

B Vitamin Interactions

Interdependence among B vitamins affecting absorption, metabolism, and excretion, exemplified by folate and vitamin B12 interaction.

B Vitamin Coenzymes

Coenzymes like NAD, TPP, CoA, and PLP derived from B vitamins, crucial for metabolic pathways and energy production in the body.

B Vitamin Deficiencies

Lack of B vitamins leading to severe consequences like pellagra from niacin deficiency, affecting skin, nervous system, digestion, and energy metabolism.

Iron-deficiency Anemia

A condition where the body lacks enough iron to produce sufficient red blood cells, leading to fatigue and weakness.

Folate Deficiency

A condition resulting from insufficient folate intake, causing symptoms like fatigue and weakness.

Multivitamin Supplement

A supplement containing a variety of essential vitamins and minerals, including iron, to cover potential deficiencies.

Hidden Blood Loss

Occult bleeding that may occur internally, often due to conditions like cancer, leading to fatigue and other symptoms.

B Vitamin Toxicities

Adverse effects caused by excessive intake of B vitamins, often from overusing dietary supplements.

Homeostasis

The body's ability to maintain internal stability and balance despite external changes.

Beriberi and Pellagra

Deficiency diseases caused by lack of thiamin and niacin, respectively, resolved by adjusting food intake.

Coenzymes

Molecules that assist enzymes in facilitating various biochemical reactions in the body.

Pernicious Anemia

A type of anemia caused by vitamin B12 deficiency, leading to fatigue and nerve damage.

Biotin and Pantothenic Acid

B vitamins essential for energy metabolism, commonly found in various foods.