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Vitamins and Minerals

Vitamins

• Vitamins are substances made by plants and animals (organic molecules with carbon backbone) that are required in relatively small amounts.

• Vitamins function as co-enzymes – needed for enzymes to work

• Any vitamin that is missing from the diet will cause a specific deficiency.

Vitamins • Fat soluble:

– A,D,E,K

– Carried in the blood by protein carriers, can be stored in the liver and other fatty tissues and may build up to toxic concentrations

• Water soluble: – B vitamins – thiamin (B1), riboflavin (B2), niacin

(B3), folate, vitamin B12, vitamin B6, biotin, pantothenic acid, Vitamin C

– Absorbed directly into the blood stream, not stored in any tissues, excesses are excreted in urine

Vitamin A

• Retinol and other forms, or carotenoids from plants

• Involved in immune function, and critical for vision as a part of the light perception of the retina

• Preformed vitamin A is found in foods from animal sources such as dairy, fish, meat (especially liver)

• Provitamin A – beta-carotene is converted by the body into the active form – is found in orange fruits and vegetables such as sweet potato, carrots and leafy green vegetables

Vitamin A deficiency

• Deficiency is rare in Canada, but common in many developing countries, because residents have limited access to animal products, and foods containing beta-carotene due to poverty.

• The most common symptom of vitamin A deficiency is blindness which starts out as night blindness.

• Deficiency also causes increased risk of infections due to weak immune response.

Health Risks

• Excess intake of preformed vitamin A can be toxic.

• Arctic explorers who ate polar bear liver experienced a range of symptoms including death.

Vitamin D

• Unique – the body can synthesize all it needs with the help of sunlight

• Maintains calcium and phosphorus levels for strong bones

• Deficiency is the disease rickets – softening of the bones.

Vitamin D

• Chronic excess ingestion of vitamin D may be toxic to the body – anorexia, and calcium deposits in soft tissue

• When UV light from the sun shines on a cholesterol compound in human skin the compound is transformed into vitamin D precursor

• Dark skinned people require longer exposure to direct sun than light skinned for vitamin D production

• Vitamin D is also found in fortified milk

Vitamin E - Tocopherol

• An antioxidant – defends the body against oxidative damage

• No Vitamin E deficiency in humans since the vitamin is found in many foods

• Also the body stores vitamin E

• Found in raw oils – but destroyed by cooking

Vitamin K

• Help make proteins that help clot blood

• Also necessary for bone formation

• Can be obtained from non-food source:

– Intestinal bacteria synthesize vitamin K

• Also available in green leafy vegetables such as spinach and cabbage.

Water soluble vitamins

• The B vitamins and vitamin C are easily absorbed from food, but any excess is also easily excreted in urine.

• B vitamins are coenzymes – a molecule that combines with an enzyme for it to function properly

• The active forms of thiamin, riboflavin, niacin, pantothenic acid and biotin participate in the release of energy from carbohydrate, fat and protein

• Vitamin B6 helps the body use amino acids to make proteins

• Folate and vitamin B12 help cells to multiply, important for cells that reproduce frequently

Thiamin and Riboflavin

• Thiamin deficiency is beriberi – edema (fluid accumulation) or muscle wasting

• Riboflavin deficiency occurs with thiamin deficiency but symptoms are not as severe.

• A diet that contains sufficient thiamin will also have enough riboflavin.

• Found in milk, black beans, enriched cereal, and yogurt

Niacin

• Niacin participates in energy metabolism.

• Niacin can be formed from eating the amino acid tryptophan

• Deficiency is pellagra which was prevalent in diets relying on corn for protein source.

• Niacin or tryptophan is found in meat, and enriched cereal.

Folate

• Women of childbearing age should consume a folate supplement as prevention, since the defects occur in the first days or weeks of pregnancy.

• Folate is added to cereals, but also found in asparagus, and beef liver.

• Helps to make DNA, necessary for new cells

• Folate deficiency is associated with a group of birth defects called neural tube defects.

Vitamins B12 and B6

• Vitamin B12 works closely with folate. Involved in proper nerve function

• Deficiency symptoms begin with anemia, but more severe symptoms such as paralysis and malfunctioning of nerves occur if deficiency continues.

• B12 is only available through animal sources, such as cheese, and meat, so vegans, vegetarians, may become deficient.

• Vitamin B6 helps to convert amino acid into another essential nutrient.

Biotin and Pantothenic Acid

• Important in energy metabolism, as coenzymes for metabolism of carbohydrate, fat and proteins

• Healthy people eating ordinary diets are not at risk for deficiences.

Vitamin C

• Two hundred years ago sailors on long voyages often died of scurvy. Doctors attempting to treat the disease found that citrus fruits cured the disease, and later scientists discovered vitamin C or ascorbic acid in citrus.

• Involved in the formation of collagen – connective tissue.

• Acts as an antioxidant protecting the body, and in immune system function

• Is found in citrus fruit but also broccoli and red pepper.

Water

• Importance of water:

• Clears tissues and blood of wastes

• Serves as a solvent for minerals, vitamins, amino acids, glucose, and other small molecules

• Actively participates in many chemical reactions

• Serves as a shock absorber in eyes, spinal cords, joints

• Aids in maintaining the body’s temperature

How much water do you need to drink?

• Water needs vary greatly depending on the food a person eats, the environmental temperature and humidity, and the person’s activity level.

• Under normal conditions adults need between 1 and 1.5 milliliters of water from all sources for each calorie spent in the day.

• A person who expends about 2000 calories needs between 2 and 3 litres of water.

Signs of dehydration

• Mild (a loss of less than 5% of your body weight)

– Thirst

– Sudden weight loss

– Rough dry skin, dry mouth, throat, body linings

– Rapid pulse

– Low blood pressure

– Severe

Signs of dehydration

• Severe (a loss of more than 5% of your body weight) – Pale skin

– Bluish lips, fingertips

– Confusion, disorientation

– Rapid, shallow breathing

– Thickening of blood

– Shock, seizures

– Coma, death

Calcium

• Most abundant mineral in the body, 99% stored in bones and teeth

• Both calcium and phosphorus are needed for bone formation

• Calcium is present in blood at a constant level

• Calcium in body fluids is important for: – Nerve transmission, blood pressure, blood

clotting, muscle contraction and activating enzymes.

Calcium

• Recommended intakes are highest for adolescents since bone growth is active.

• Adults after 40 begin to lose bone density, and need to get sufficient calcium.

• Calcium is present in dairy products, and also broccoli and turnip greens

Phosphorus

• Phosphorus is a part of the DNA and RNA of every cell, and is essential for growth and renewal of tissues

• Phosphorus deficiencies are unknown since phosphorus is abundant in cells

• Foods that contain phosphorus include dairy products, meats, and legumes

Magnesium

• Critical to many cell functions as a part of the enzyme machinery

• Magnesium is also important for proper functioning of the heart

• Magnesium deficiency may be related to cardiovascular disease, heart attack, and high blood pressure

• Most people receive only 75% of recommended magnesium

• Magnesium can be found in spinach, avocado, yogurt and black beans

Sodium

• Chemically sodium is the positive ion in the compound sodium chloride (table salt) and a gram of salt contains 400 milligrams of sodium

• The amount of sodium most diets contain is more than 2300 mg.

• Sodium is present in high levels in many processed foods.

• Sodium is a major part of the body’s fluid and electrolyte balance and acid-base balance

• High intake of sodium causes temporary higher blood pressure as more water is needed to offset the amount of salt in the body

• Excess sodium is filtered by the kidneys while they also remove excess water with the salt.

Potassium

• Plays a major role in maintaining fluid and electrolyte balance, and it is critical for maintaining the heartbeat

• Potassium deficiency is unlikely

• All living cells contain potassium, so fresh foods are the best source, such as: bananas, melons, and baked potato

Iodine

• Iodine is needed in very small amounts.

• It is a part of thyroxine a hormone made by the thyroid gland.

• This hormone regulates basal metabolic rate

• In iodine deficiency the cells of the thyroid enlarge and can become a visible lump, in pregnant women the deficiency results in serious mental retardation.

• All table salt is iodized in Canada

Iron • Most of the iron in the body is found in

hemoglobin in red blood cells, or myoglobin in muscle cells

• Iron helps these proteins to hold and carry oxygen

• The body recycles the iron that is in blood cells, so bleeding can cause significant iron loss

• Iron deficiency can lead to anemia where red blood cells don’t contain enough hemoglobin.

• A person with anemia will have a diminished supply of oxygen, resulting in tiredness, apathy and a tendency to feel cold.

• Women require 1.5 times more iron in their diet.

• Iron is present in spinach, swiss chard, enriched cereal and red meat