Vitamins & MineralsMetabolism

Remember this? … specific mechanisms of absorption for the vitamins and minerals will not be covered in this course… just recall the effects of fiber (or lack thereof) and imagine how it may affect absorption of vitamins & minerals…

Some Notes on Vitamin & Mineral Uses

Mg++ must be present for the ATP (or ADP) to bind

To synthesize ATP molecule in the first place you need Folic Acid, Thiamine, Cobalamin, PO4, Zn+, Cr++, & Mg++

Niacin is a component of NAD+

Vitamin & Mineral uses are illustrated within the metabolic pathways . . .

Obviously, in order for the metabolic pathways to work, the enzymes (proteins) must be synthesized in the first place . . .

Some Nutritional Requirements For This Process Include:

Protein synthesis- requires DNA, RNA, mRNA, GTP . . .- synthesis enzymes require Cr+?, Mg++, Zn+ to function

and amino acids for structure

Synthesis of DNA, RNA, ATP, GTP . . .- folic acid, B12, glucose, aa, PO4 (structure)

You’ve seen this before . . .

Only now it is labeled with some nutrient requirements

In the previous slide, transcription was activated by the signaling molecule (estrogen) binding to the actual promoter – resulting in dimerization and DNA binding.

Other signaling molecules (growth hormone, calcium / diacyl-glycerol, interleukins, various growth factors, and a host of others) can activate promoters by activating an enzyme cascade which ultimately results in promoter activation.

More Notes onVitamin & Mineral Uses

Thiamin is a component of PDH & αKGDH

Riboflavin is a component of FAD+

Iron and Sulphur are part of the enzyme Aconitase

Pantothenic Acid is a component of CoA

Pyridoxine (as pyradoxal phosphate) is a cofactor for transamination reactions

And More Notes onVitamin & Mineral Uses

Iron is a component of complex III and cytochrome c and both Iron and Copper are components of cytochrome c oxidase

Ascorbic Acid is necessary for the synthesis of carnitine

Even More Notes on Vitamin & Mineral Uses

Riboflavin, Iron, and Sulphur are components of complex I

Iron and Sulphur are part of the CoQ complex

Dietary Notes On Some Vitamins & Minerals

RDA Food Sources

Magnesium 19 – 30 yrs 310 & 400 mg/day ♀ & ♂ Dark green vegetables, milk, tea, coffee, cocoa, whole grain

31 to 50 yrs 320 & 420 mg/day ♀ & ♂ cereals

Folic Acid 400 µg /day ♀ & ♂ High levels in yeast, organ meats, fresh green vegetables, some fresh fruits

Thiamine (B1) 1.1 & 1.2 mg/day ♀ & ♂ Whole grain cereals, organ meats, lean pork, and yeast

Cobalamin (B12) 2.4 µg/day ♀ & ♂ Organ meats, meat and meat products, clams, oysters, legumes

Niacin 14 & 16 mg/day ♀ & ♂ Yeast, lean meats, liver, legumes, and poultry

Riboflavin (B2) 1.1 & 1.3 µg/day ♀ & ♂ Eggs, lean meats, organ meats, green leafy vegetables, enriched cereals

Pantothenic Acid (AI) 5 mg/day ♀ & ♂ Ubiquitous: high levels in animal protein, legumes, and whole‑grain cereals

Pyridoxine (B6) 1.3 mg/day ♀ & ♂ Meats, poultry, fish, wheat bran, some in: milk, eggs, green leafy vegetables

Ascorbic Acid 75 & 90 mg/day ♀ & ♂ Citrus fruits and strawberries, tomatoes, potatoes, broccoli, cauliflower, spinach, cabbage, and brussel sprouts

Phosphorus 700 mg/day ♀ & ♂ Ubiquitous: milk & dairy, meats, phosphoric acid in carbonated drinks

Zinc 8 & 11 mg/day ♀ & ♂ lots in shellfish, egg white, some in most animal and plant foods

Chromium (AI) 25 & 35 µg/day ♀ & ♂ Mushrooms, brewers' yeast, prunes, nuts, asparagus, eggs, shellfish, cereals (bran), wine, beer

Iron 18 & 8 mg/day ♀ & ♂ Meats, liver, clams, oysters, dried fruits, nuts, cereal products

Sulphur None necessary All protein foods

Copper 900 µg/day ♀ & ♂ Shellfish and legumes, bananas, potatoes, bran, liver

Food Group Sources of Vitamins & Minerals

Dairy Fruits Veggies Meats & Beans & Nuts & Breads & Eggs Legumes Seeds Cereals

Magnesium X Green X X

Folic Acid X Green X

Thiamine (B1) X X

Cobalamin (B12) X X

Niacin X X

Riboflavin (B2) Green X X (enriched)

Pantothenic Acid X X X

Pyridoxine (B6) X Green X X

Ascorbic Acid X Green

Phosphorus X X

Zinc X X

Chromium X (prunes) X X X (bran)

Iron X (dried) X X X

Copper X Starchy X X X (bran)

Food Servings for Different Caloric Intakes - (Adapted from Optimal Health Guide)

1900 2200 2500 2800 3100 3400 3700kCal*

Dairy 3 3 3 3 3 3 3

Fruits 4 4 5 6 7 7 7

VeggiesGreen 2 2 3 3 4 4 4Yellow 1 1 2 2 3 3 3Starchy 1 1 1 2 3 3 3Other 2 3 3 3 3 3 3

Meats / Fish / Eggs0 1 1 1 1 1 2

Beans & Legumes / 2 3 3 3 3 4 4Nuts & Seeds 1 1 1 1 1 1 2

Breads / Cereals 5 6 7 9 11 13 14

Added Fats 2 2 2 3 3 3 4

*1900 kCal intake meets RDA requirements on average; 2200 or more exceeds requirements . . .

Oxygen Radicals and Antioxidants

Remember that various electron carriers such as NADH, FADH2, & Co-Q can auto-oxidize to produce superoxide anions or hydrogen peroxide . . . In the presence of ferric iron (3+), this reaction is greatly speeded up . . .

Reactive Oxygen Species (ROS) can damage many different molecules in cells - leading to a variety of serious problems . . . the production of various carcinogens from peroxidized lipids is just one possible outcome . . .

Vitamin E reacts with a peroxyl radical to become a stable radical

Vitamin C also reacts with ROS to become a stable radical

Dehydroascorbate & ascorbate radical can be reduced back to ascorbate . . .

Once a stable vitamin E radical has been formed. It can be reduced by vitamin C, which, in turn, can be reduced by glutathione

Continual recycling between vitamin E, vitamin C, and glutathione ensures a stable antioxidant environment . . . dependant on continued synthesis of glutathione and consumption of vitamin c

β-Carotene is a very effective singlet-oxygen scavenger

β-Carotene also can function as a chain-breaking antioxidant . . . though not nearly as well

Dietary Notes On Some Antioxidant Vitamins

RDA Food Sources

Ascorbic Acid 75 & 90 mg/day ♀ & ♂ Citrus fruits and strawberries, tomatoes, potatoes, broccoli, cauliflower, spinach, cabbage, and brussel sprouts

α-tocopherol 15 mg/day ♀ & ♂ Vegetable oils and wheat germ

Carotenoids N/A Tomatoes, green & yellow vegetables(ß-carotene, lutein,lycopene . . .)

Food Group Sources of Antioxidants

Dairy Fruits Veggies Meats & Beans & Nuts & Breads & Oils Eggs Legumes Seeds Cereals

Ascorbic Acid X Green

α-tocopherol X X (vegetable)

Selenium X X

Carotenoids greenyellow

Other antioxidant compounds (phytochemicals)exist and are easily obtained in the diet. . .

(later!)

Enzymatic Antioxidant Systems

Zinc / Copper: cytosolic / extra cellularMn: mitochondrial SOD

Fe

Dietary Notes On Requirements for Some Antioxidant Enzymes

RDA Food Sources

Iron 18 & 8 mg/day ♀ & ♂ Dried fruits, nuts, cereal products, organ & other meats - component of catalase seeds, green leafy vegetables

Zinc 11 & 8 mg/day ♀ & ♂ Wheat germ, whole grains, beef, poultry, oysters - component of cytosolic & extracellular superoxide dismutase Copper 900 ug ♀ & ♂ Whole grains, liver, legumes, eggs, meats, shellfish - component of cytosolic & extracellular superoxide dismutase

Manganese 1.8 & 2.3 mg/day ♀ & ♂ Wheat bran, nuts, poultry, legumes, meat - component of mitochondrial superoxide dismutase

Selenium 35 µg/day ♀ & ♂ Seafood, organ and red-meats, whole grains, dairy - component of glutathione peroxidase

Food Group Sources of Antioxidants

Dairy Fruits Veggies Meats & Beans & Nuts & Breads & Oils Eggs Legumes Seeds Cereals

Iron X X X X XGreen leafy

Zinc X Xbeef/poultryoysters

Copper X X Xeggs/meatsshellfish

Manganese X X Xbeef/poultry

Selenium X X Xorgan/red meatsfish

Repeated exercise will enhance these enzyme systems in muscle, liver, lung, brain, etc . . . raising the issue that in spite of some claims by the “health-food” industry . . . there may be no real enhanced nutritional requirement for the vitamin antioxidants with exercise . . .

Unfortunately, the average american

dietReally Sucks . . .

Adapted from Nutrition for Sport and Exercise, Dunford & Doyle, 2008

Resulting in an almost non-existent probability of being adequate . . .

Adapted from Nutrition for Sport and Exercise, Dunford & Doyle, 2008