Vitamins and Phytochemicals
Vitamins
Essential organic substances
Produce deficiency symptoms when missing from diet
Yield no energy
Basic functions:
Facilitate energy-yielding chemical reactions
Function as co-enzymes
Fat-soluble vitamins
A, D, E and K
Absorbed with fat
Transported by protein carriers
Stored in large amounts in liver and fatty tissues
More time to become deficient
Highly toxic—especially Vitamin D and A
Dissolve in lipids or solvents
Water-soluble vitamins
B Vitamins:
B6
B12
Thiamin
Niacin
Folate
Riboflavin
Biotin
Pantothenic acid
Vitamin C
Stored in small amounts
Readily excreted from the body
Not extensively stored
Less toxic (usually)
High doses excreted (urine)
Takes less time for deficiency to develop—due to limited stores
Folate
Required to produce new cells
Red blood cells
Functions
DNA synthesis
Red Blood Cell (RBC) formation
Birth defect prevention (neural tube defects)
RDA
Males- 400 micrograms
Females- 600 micrograms (during child-bearing years)
Coenzyme
DNA synthesis
Homocysteine metabolism
Neurotransmitter formation
Sensitive to:
Heat, oxidation, ultraviolet light
Deficiency
Anemia (Megaloblastic)—large, immature red blood cells
Heart disease—Low levels of folate may increase Homocysteine levels
Homocysteine linked to plaque formation
Neural tube defects—A defect in the formation of the neural tube (spinal cord, brain) during early fetal development
Neural tube defects
Neural tube develops in 1st month of gestation
Defect occurs when spinal column or skull don’t form properly
Spina Bifida—failure of neural tube to close
Spinal cord bulges through the back
Sources:
Enriched pasta, cereal, rice and bread
Organ meats (liver, kidney)
Sprouts
Dark green leafy vegetables
Beans
Orange Juice
All women of childbearing age 400ug/day (neural tube forms before most women know they are pregnant)
B- Vitamins
Many of the B-vitamins are co-enzymes
Co-enzymes are needed for the enzymes to do their job
Most B-vitamins help release energy into the body from food
Uses:
Energy Metabolism (from carbohydrates, protein, and fat)
Thiamin, Niacin, Biotin, Riboflavin, Pantothenic Acid
Amino Acid Metabolism (enzyme/hormone production)
Vitamin B6
Cell synthesis
Folate & Vitamin B12
Vitamin D
Function
Helps in absorption of calcium and phosphorus in the gut, kidney, and bone
Hormone:
Regulates blood calcium levels
Regulates bone metabolism
Prohormone- works like a hormone, sends signals to organs
Derived from cholesterol
Synthesized from sun exposure
Sunscreen SPF > 8 decreases synthesis 95%
Expose hands, face, arms 2-3xs a week for 5-10 minutes each time (more for darker skin)
RDA (adults)
5- 15 micrograms
Insufficient sun exposure makes this a vitamin (have to get it through diet)
Activated by enzymes in liver and kidneys:
Vitamin D 25-hydroxyvitamin D (Liver) 1,25-dihydroxyvitamin D—active hormone (Kidneys)
Need to have a healthy liver and kidney in order to utilize Vitamin D properly
Toxicity Warning:
Vitamin D can be very toxic, especially in infancy and childhood
Upper Level is 50ug/day
Results in
Over-absorption of calcium (hypercalcemia), increase calcium excretion
Calcium deposits in organs and blood vessels
Growth retardation
5X RDA
Sources
Exposure to UV radiation (sunlight)
Fortified milk
Fatty fish
Salmon
Shrimp
Sardines
Eggs
Butter
Liver
Deficiency
Rickets in children
Bowed legs (bones can’t support the weight of the body)
Osteomalacia (adults)
Soft bones
Groups at risk for deficiency:
Elderly, ill, homebound
Those with limited sun exposure and poor intake of Vitamin D rich foods
Darker skin
Vitamin A
Function
Bone formation
Promotes growth
Promote vision
Night blindness
Vision in dim light
Prevent drying of the skin and eyes
Xerophthalmia
Reproduction, growth, development
Cancer prevention
Promote immune function and resistance to bacterial infection
Acne medication
Neutralizes free radicals in nonsmokers
Beta-carotene
RDA (adults)
900 RE- Males
700 RE- Females
