NUSCTX 10, Midterm 2 - UC Berkeley

Fat-Soluble Vitamins

Vitamin A

Vitamin D

Vitamin E

Vitamin K

Water-Soluble Vitamins

B complex plus vitamin C

Required in diet

Act as enzyme cofactors

Deficiencies used to be common

People on poor diets often deficient in multiple vitamins

B Vitamins

Thiamin (B1)

Riboflavin (B2)

Niacin (B3)

Biotin

Pantothenic Acid

Vitamin B6

Folate

Vitamin B12

Dietary Reference Intakes

Adequate Intake

Tolerable Upper-Intake Level

Estimated Average Requirement

Recommended Dietary Allowance

Properties of Water Soluble Vitamins

Dissolve in water

No real stores

Readily excreted

Function: coenzymes and antioxidants

Absorbed by portal system

Not required daily

High doses can be toxic

Subject to cooking and food storage losses

Properties of Fat Soluble Vitamins

Fat soluble

Stored in tissues

Remain in adipose and liver

Function: hormones, blood clotting, antioxidants

Absorbed by lymphatic system with fats (chylomicrons)

Not required daily

High doses can be toxic

Digestion of fat soluble vitamins

Require bile acids for absorption

Require digestive enzymes for absorption

Absorbed in the similar manner of fats

Little vitamin K production by gut bacteria

Retinol

Vitamin A

Retinal

Visual Cycle

Retinoids

Support development, growth, reproduction

Epithelia (skin, respiratory, and digestive systems)

Immune System

Nervous System

Vitamin A in the Liver

Liver breaks down some vitamin A into retinoic acid and saves the rest for storage

Retinoic Acid

Reproduction

Nervous System

Epithelia (skin)

Immune Function

Recommended Dietary Allowance of Vitamin A

0.3 mg to 1.3 mg: age, sex, pregnancy, lactation

Toxic Intake

100 fold > RDA in adults

20 fold > in children

Vitamin K

Koagulation

Mechanism of Vitamin K Action

i) Targeted Protein (e.g. prothrombin)

ii) Vitamin K-dependent enzyme

iii) Modified Protein Binds Ca++(e.g. thrombin)

Vitamin K-Dependent Enzymes

Activate specific target proteins by enabling them to bind to calcium.

Vitamin K Functions

Essential for activating proteins required for:

Blood clotting

Blood vessel repair

Bone density

Preventing soft-tissue calcification

Warfarin

A vitamin K antagonist that retards blood coagulation

Vitamin E

Most potent lipid-soluble anti-oxidant known.

Vitamin E protects polyunsaturated fatty acids from oxidative damage.

Vitamin E protects membranes and low density lipoproteins from oxidative damage

Vitamin D

Cholecalciferol

The sunshine vitamin

Vitamin D Synthesis and Metabolic Activation

Pre-Vitamin D3

Vitamin D3

25-OH-D3

Calcitriol

Calcitriol

Hormone produced from Vitamin D3, is the only hormone that can induce the intestine to absorb dietary Ca++

Hypocalcemia

Deficiency of calcium in the bloodstream; leads to tetany and ultimately death.

Hypercalcemia

Condition in which calcium in the bloodstream is above normal; leads to soft-tissue Ca++ and ultimately death.

Rickets

Osteomalacia

Lack of Ca++/Vitamin D

Failure to convert vitamin D into calcitriol

Failure of calcitriol to regulate gene expression

Osteomalacia

Organic bone matrix normal, but not calcified

Matrix > calcium

Osteoporosis

Matrix/calcium ratio normal, both reduced

Thin and brittle bones

Osteoporosis Risk Factors

Being female

Race (white, Asian)

Menopause

Small stature

Sedentary

Vitamin D Recommended Dietary Allowance

15 micrograms/day

Dietary needs depends on skin color, sunlight exposure, and other factors

High levels toxic

Good source of Vitamin D

Liver (cod liver oil)

Milk

Meat

Beans

Bone Remodeling

Bone mass is maintained by continual degradation of existing bone and synthesis of new bone.

Bone Remodeling Facilitates

Adjustment to new strength level

Adjustment to new shape

Replacement of degrading matrix ( collagen proteoglycan) during normal turnover

Osteoblasts

Cells that produce the protocollagen and proteoglycans that ultimately constitute the "matrix" of bone.

Vitamin C is involved in protocollagen sythesis.

Osteocytes

Osteoblasts that become entrapped in the polymerizing collagen fibers.

Osteoclasts

Act to degrade bone.

Calcitonin

Secreted by the thyroid gland when plasma and Ca are high

Calcitonin Effects

Reduces osteolytic activity

Reducing formation of new osteoclasts

Increasing osteoblast activity

Functions of Calcium

Bone mineralization

Stabilize complexes

2nd messenger

Neurotransmission

Fertility

Muscle contraction

Enzyme activity

Intracellular adhesion

Functions of Phosphorus

Bone mineralization

Energy transfer

Acid-Base buffer

Component of RNA & DNA

Protein modification

Signaling molecules

Phospholipids

Structural component of teeth

Energy Releasing B Vitamins

Thiamin

Riboflavin

Niacin

Pantothenic acid

Biotin

Vitamin B6

Hematopoietic B Vitamins

Folic acid

Vitamin B12

Vitamin B6

Pantothenic acid

Thiamin Vitamin Deficiency

Beriberi

Damage to nervous system, heart

Muscle weakness and wasting, edema

Common in alcoholics

Thiamin

Vitamin B1

Thiamin RDA

Men: 1.2 mg/day

Women 1.1 mg/day

Thiamin: Chief Functions in the Body

Part of coenzyme TPP (thiamin pyrophosphate) used in energy metabolism

Thiamin: Significant Sources

Whole-grain

Fortified or enriched grain products

Moderate amounts in all nutritious food

Pork

Easily destroyed in heat

Thiamin: Deficiency Disease

Beriberi

Wet, with edema

Dry, with muscle wasting

Thiamin: Deficiency Symptoms

Enlarged heart

Cardiac failure

Muscular weakness

Apathy

Poor short-term memory

Confusion

Irritability

Anorexia

Weight loss

Riboflavin

Vitamin B2

Riboflavin RDA

Men: 1.3 mg/day

Women: 1.1 mg/day

Riboflavin: Chief functions in the Body

Part of coenzymes FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide) used in energy metabolism

Riboflavin: Significant Sources

Milk products

Whole-grain

Fortified or enriched products

Liver

Easily destroyed by ultraviolet light and irradiation

Riboflavin: Deficiency Disease

Ariboflavinosis

Riboflavin: Deficiency Symptoms

Sore throat

Cracks and redness at corners of mouth

Painful, smooth, purplish red tongue

Inflammation characterized by skin lesions covered with greasy scales

Niacin

Nicotinic acid

Nicotinamide

Niacinamide

Vitamin B

Niacin RDA

Men: 16 mg NE/day

Women: 14 mg NE/day

Niacin UL

Adults: 35 mg/day

Niacin: Chief Functions in the Body

Part of coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (its phosphate form) used in energy metabolism

Niacian: Significant Sources

Milk

Eggs

Meat

Whole-grain

Fortified and enriched grain products

Nuts and all protein-containing foods

Niacin: Deficiency Disease

Pellagra

Niacin: Deficiency Symptoms

Diarrhea

Abdominal pain

Vomiting

Inflamed, swollen, smooth, bright red tongue

Depression, apathy, fatigue

Loss of memory, headache

Niacin: Toxicity Symptoms

Painful flush

Hives and rash

Nausea and vomiting

Liver damage

Impaired glucose tolerance

Pyridoxine

Vitamin B6

Pyridoxal

Pyridoxamine

Pyridoxine RDA

Adults (19-50 yr): 1.3 mg/day

Pyridoxine UL

Adults: 100 mg/day

Pyridoxine: Chief Functions in the Body

Part of coenzymes PLP (pyridoxal phosphate) and PMP (pyridoxamine phosphate) used in amino acid and fatty acid metabolism

Helps to convert tryptophan to niacin and to serotonin

Helps to make red blood cells

Pyridoxine: Significant Sources

Meats

Starchy vegetables

Legumes

Non-citrus fuits

Fortified cereals

Liver

Soy products

Easily destroyed by heat

Pyridoxine: Deficiency Symptoms

Scaly dermatitis

Anemia

Depression

Confusion

Convulsion

Pyridoxine: Toxicity Symptoms

Depression, fatigue, irritability

Headaches

Nerve damage causing numbness and muscle weakness

Inability to walk and convulsion

Skin Lessions

Pantothenic Acid

Part of coenzyme A

Used in energy metabolism

Pantothenic Acid: AI

Adults: 5 mg/day

Pantothenic Acid: Significant Sources

Widespread in foods

Chicken

Beef

Potatoes

Oats

Tomatoes

Liver

Egg yolk

Broccoli

Whole-grains

Pantothenic Acid: Deficiency Symptoms

Vomiting, nausea, stomach cramps

Insomnia, fatigue, depression, irritability, restlessness, apathy

Hypoglycemia, increased sensitivity to insulin

Numbness, muscle cramps, inability to walk

Biotin

Part of a coenzyme used in energy metabolism

Fat synthesis

Amino acid metabolism

Glycogen synthesis

Biotin: AI

Adults: 30 micrograms/day

Biotin: Significant Sources

Widespread in foods

Liver

Egg yolks

Soybeans

Fish

Whole-grains

Produced by GI bacteria

Biotin: Deficiency Symptoms

Depression, lethargy, hallucinations

Numb or tingling sensation in arms and legs

Red, scaly rash around the eyes, nose and mouth

Hair loss

Vitamin C

Ascorbic Acid

Vitamin C RDA

Men: 90 mg/day

Women: 75 mg/day

Smokers: +35 mg/day

UL

Adults: 2000 mg/day

Vitamin C: Chief Functions in the Body

Collagen synthesis

Antioxidant

Thyroxin synthesis

Amino acid metabolism

Strengthens resistance to infection

Helps in absorption of iron

Vitamin C: Significan Sources

Citrus fruits

Cabbage-type vegetable

Dark green vegetables

Strawberries

Lettuce

Tomatoes

Potatoes

Papayas

Mangos

Easily destroyed by heat and oxygen

Vitamin C: Deficiency Disease

Scurvy

Vitamin C: Deficiency Symptoms

Anemia

Atherosclerotic plaques

Pinpoint hemorrhages

Bone fragility, joint pain, poor wound healing

Frequent infections

Bleeding gums, loosened teeth

Muscle degeneration

Pain, hysteria, depression

Rough skin, blotchy bruises

Folate

Folic acid

Folacin

Pteroylglutamic

Folate RDA

Adults: 400 micrograms/day

Folate UL

Adults: 1000 micrograms/day

Folate: Chief Functions in the Body

Part of coenzymes THF (tetrahydrofolate) and DHF (dihydrofolate) used in DNA synthesis and therefore important in new cell formation

Folate: Significant Sources

Fortified grains

Leafy green vegetables

Legumes

Seeds

Liver

Folate: Deficiency Symptoms

Anemia

Smooth, red tongue

Mental confusion

Weakness, fatigue, irritability

Headache

Shortness of breath

Elevated homocysteine

Cobalamin

Vitamin B12

Cobalamin RDA

Adults: 2.4 micrograms/day

Cobalamin: Chief Functions in the Body

Part of coenzymes methylcobalamin and deoxydenosylcobalamin used in new cell synthesis

Helps to maintain nerve cells

Reforms folate coenzyme

Helps to break down some fatty acids and amino acids

Cobalamin: Significant Sources

Foods of animal origin

Fortified cereals

Cobalamin: Deficiency Disease

Pernicious anemia

Cobalamin: Deficiency Symptoms

Anemia

Fatigue, degeneration of peripheral nerves

Paralysis

Sore tongue

Loss of appetite

Constipation

Iron

Most common nutritional deficiency worldwide

Estimated that 2 billion people may be deficient

Excess iron also major problem as free iron is toxic and causes oxidative damage

Too little iron

Reduced oxygen-carrying capacity and energy generation (esp. in women, children)

Too much iron

Free radical mediated damage

Susceptibility to infection

Risk of heart disease, especially in men