Chapter 10 Human Nutrition

What is the dietary adequacy of Folate?

Adult RDA is 400 ug/day - May be measured in micrograms Risk of folate deficiency: - During periods of rapid growth, such as pregnancy, infancy, and childhood - With excess alcohol consumption

Cells require vitamin _ to make coenzymes that participate in various cellular processes, including the transfer of methylation in folate metabolism.

B-12

What is Riboflavin (B-2)?

Coenzyme component of flavin adenine dinucleotide (FAD). [FAD plays major role in energy production. Cellular function, growth, and development). Found in: cow's milk, yogurt, mushrooms, and green leafy vegetables. Deficiencies are extremely rare in the U.S. - Those of greatest concern have endocrine disorders - Signs are swollen toungue (glossitis), crack in corners of mouth (cheilosis) - ariboflavinosis.

What are coenzymes?

Most water-soluble vitamins function as coenzymes. Coenzymes are small molecules that interact with enzymes, enabling the enzymes to function.

Which vitamin plays a role in the chemical reactions involved in the release of energy from carbohydrates?

Thiamin (B-1)

Vitamin-like compounds include

choline, carnitine, lipoic acid, inositol

When a water-soluble vitamin assists in the chemical reaction involved in the metabolism of the macronutrients, this is known as its _____ function

coenzyme

Biotin's roles in the body includes ______.

glucose synthesis amino acid breakdown fatty acid synthesis

A healthy diet designed to reduce cancer risk would include

increasing your intake of fruits. increasing your intake of whole grains. limiting consumption of red meat.

What are some major food sources of vitamin B-12?

meat, poultry, milk

In chemical reactions involved in the metabolism of macronutrients, water-soluble vitamins are

used as coenzymes.

In its coenzyme form, biotin participates in chemical reactions that

add carbon dioxide to other compounds.

Because exposure to tobacco smoke increases free radical formation in the lungs, smokers have a higher requirement for vitamin _____ .

c

Folate digestion and absorption

Folate naturally occurs in foods as folate polyglutamate; the synthetic form is folic acid or folate monoglutamate. Measured in micrograms of dietary folate equivalents. Food sources: leafy vegetables (broccoli, asparagus), legumes, orange juice, enriched grain products, fortified cereals, and liver.

Which of food groups provide the highest levels of vitamin C in the body?

Fruits and vegetables

_______ is a toxic amino acid and vitamin B-6 plays a vital role in keeping it from accumulating in the blood.

Homocysteine

What are the functions of Thiamin pyrophosphate (TPP)?

Involved in many reactions of carbohydrate metabolism and protein metabolism. Helps make neurotransmitters.

What is biotin?

Is a component of a coenzyme that participates in chemical reactions that add carbon dioxide to other compounds. Regenerates oxaloacetate in the citric acid cycle. Food sources: eggs, liver, peanuts, salmon, pork. (Intestinal bacteria also produces). The only group of people that may need to be concerned with higher levels are pregnant and breastfeeding women, as well as infants.

Thiamin (B-1) deficiencies

- Beriberi (weakness, poor muscular coordination, and abnormal nervous, cardiovascular system function) - Wernicke-Korsakoff syndrome (degenerative brain disorder associated with excess alcohol)

Functions of Vitamin B-6

- Facilitating (over 100) enzymatic reactions involving amino acid metabolism - Involved in the conversation of tryptophan to niacin - Involved in the transamination reaction that form nonessential amino acids - Involved in synthesis of neurotransmitters - Helps produce heme (found in hemoglobin) - A last, significant, function is to convert homocysteine to cysteine. (Homocysteine is an amino acid that is a toxic byproduct methionine metabolism)

What are the important functions of folate?

- Involved with energy metabolism - DNA synthesis and amino acid metabolism - Involved in homocysteine metabolism

What are the functions of niacin?

- involved in at least 200 reactions - involved in the pathway that releases energy from macronutrients - used to make NAD and NADP

steps involved in cancer development and progression

1. The gene that control cell division in a healthy, specialized cell is damaged by a carcinogen. 2. With repeat damage, one abnormal cell divides uncontrollably. 3. Malignant cells become a tumor. 4. Invasive cell multiples, tumor grows and interferes with normal tissue functioning. 5. Malignant cells enter circulatory or lymphatic systems (metastasize) and form new tumors in other parts of the body 6. Tumor stimulates development of its own blood supply

What is folate?

Coenzyme component of tetrahydrofolate (THF) - Folate comes in a couple of forms, food folates and folic acid Folate interacts with a couple of B vitamins - B-6 & B-12

What is Thiamin (B-1)?

Coenzyme component of thiamin pyrophosphate (TPP) Food sources: pork, whole gains, enriched breads, legumes, nuts. (overheating food can kill thiamin)

What are the functions of Vitamin C?

Collagen synthesis Immune system functioning

What is pantothenic acid?

Component of coenzyme (CoA). Helps release energy from carbohydrates, fat, and proteins. Found in: some fortified cereals, shitake mushrooms, sunflower seeds. Deficiency: Rare (alcoholics), burning feet syndrome

What is vitamin B-6?

Family of three compounds: pyridoxine, pyridoxal, and pyridoxamine. Coenzyme component of pyridoxal phosphate (PLP). Found in: pistachio nuts and walnuts, salmon, beef, potatoes and bananas, chickpeas. **Notes: Vitamin B-6 is lost during the refining process of grains and is not added back to grain products during enrichment.

What is Niacin (B-3)?

Niacin is the generic name for the two forms of Nicotinic acid and Nicotinamide. (Body uses both forms) Coenzyme component of nicotinamide adenine dinucleotide (NAD) Present in many foods, added to some food products, and available as a dietary supplement. Deficiency - pellagra (affects those who eat a lot of corn, alcoholics and those suffering from anorexia) Dermatitis, diarrhea, dementia, and death. Toxicity is not noted with food but with excess supplementing. Intestinal bacteria

A condition characterized by severe sensory nerve damage is called...

Peripheral neuropathy

What is folic acid?

Synthetic form of the vitamin that is used in fortified foods and most dietary supplements.

Shellfish, poultry, meat, and eggs are all good sources of which vitamin?

Vitamin B-12

______ plays a vital role in keeping homocysteine from accumulating in the blood by converting it to cysteine.

Vitamin B-6

In the body, pantothenic acid is important for

energy metabolism and fatty acid production

High intake of fruits and vegetables reduce the risk of cancers of the

esophagus. stomach. lungs.

What is present in fruits and vegetables, has antioxidant activity, and may help prevent cancer?

phytochemicals carotenoids vitamin C

What is added to processed meats and is classified as a carcinogen?

sodium nitrate

Anancephaly and __________ are two neural tube defects that may occur if a woman's diet is low in folate.

spina bifida

The neural tube in the human embryo eventually develops into the ______.

spinal cord brain A diet adequate in FOLATE is recommended for preventing neural tube defects.

Which form of vitamin B-12 is more readily absorbed?

synthetic form of vitamin B-12

Vitamin-like compounds are similar to vitamins except

they are not essential.

Compounds in fruits and vegetables that may help prevent cancer include

vitamin C. carotenoids. phytochemicals.

The B vitamins and vitamin C are _____ vitamins.

water soluble