Food Science Midterm 2 Review Sheet Minerals Minerals are inorganic elements Some minerals are essential for proper metabolic function Minerals may serve as cofactors for some enzymes or as structural elements The essential minerals may be classified as major or trace Vitamins are nutrients the body needs in small amounts for the function of some enzymes They are organic compounds Some enzymes require other small molecules to function that are not organic These are known as minerals As with vitamins some of these are much more likely to be in short supply than are others The ones that are most likely to be lacking or to cause problems are the ones we will concentrate on but we will discuss most of the known required minerals Calcium Calcium is the mineral found in the greatest amount in the body Comprises from 1 5 to 2 0 of the human body 99 found in bones and teeth 1 in blood Absorption of calcium is not efficient Requires Vitamin D for absorption Functions Calcium functions to add structure to teeth and bones Soluble calcium functions in Blood clotting Muscle tone and contraction Nerve transmission Some enzymatic functions The functions of soluble calcium are critically important Without calcium muscles can not contract A deficiency of soluble calcium would result in your heart stopping to beat It would also mean that your blood would not clot and your nerves would not work This cannot be allowed to happen The mineral selected for all of these functions is stored in bones If the level of soluble calcium starts to decrease the body replaces it by dissolving bone It is not good for bones to have calcium removed but weak bones are better than death One way the body removes high levels of lead from blood is to deposit it in bone When calcium is removed during times of shortage blood lead levels may increase In the past this caused serious problems for children who lived in houses with lead based paint whose intake of calories was marginal and were often lacking in calcium The removal of calcium from bone also increased the blood lead level Often this increase was enough to cause symptoms of lead poisoning The removal of lead from gasoline and paint has greatly alleviated this problem Requirements Balance studies with calcium are difficult Minimum requirement estimated to be 400 to 650 mg day RDA for adults is 800 mg day For teens the recommendation is 1 200 mg day to supply for bone synthesis Effects of calcium deficiency in children are Stunting of growth Poor quality bones and teeth Malformed bones rickets see Vitamin D In adults effects are Osteoporosis Osteomalcia Osteoporosis Word means holes in bones Results from loss of calcium from bone to meet body s other calcium needs Strong genetic age and hormonal components Results from poor calcium absorption Serious health problem Affects women past the age of menopause Medications aimed at slowing loss of calcium Experimental drugs that may replace lost calcium Weakened bones that result from osteoporosis are a major factor in broken bones among the elderly Osteoporosis does NOT result from a lack of calcium in the diet in developed countries It results from changes in calcium metabolism when the levels of sex hormones decrease in people genetically predisposed to the condition It is most common in those of northern European ancestry We normally associate Osteoporosis with females This is because females pass through menopause at a younger age than when men stop making their sex hormones Women also live longer than men In the past most men died before osteoporosis became a problem As men are living longer we are starting to see males affected by osteoporosis It is still mostly a disease of women Women who were active in their youth are at a lesser risk of developing osteoporosis than those who were more sedentary Weight bearing exercise tends to increase bone mass and calcium accumulation during periods of active bone growth This provides a greater reservoir of calcium to draw on when poor absorption becomes a problem Recently a number of medications have been developed than can not only slow the loss of calcium from bones in susceptible women but that also reverse some of the loss These medications may help to eliminate osteoporosis as a problem for people of your age It still makes sense to be sure that you consume adequate calcium and remain active during periods of active bone growth Sources of Calcium Excellent hard cheeses milk and most dark green leafy vegetables 150 300 mg Good softer cheeses ice cream broccoli legumes 100 150 mg Fair Cottage cheese oranges nuts salad greens eggs light cream 50 100 mg Poor Most fruits vegetables grains and meats You do not need to know sources of nutrients Phosphorus Phosphorus makes up approximately 1 of the human body 80 found in bones and teeth 20 in blood and other tissues The functions of phosphorus are as essential as those of calcium Calcium ions have positive charges and phosphorus ions negative charges These minerals are often found associated with each other Most of the mineral of bone is essentially calcium phosphate Functions as Buffer to maintain pH Metabolism of protein lipid and CHO Component of ATP DNA and RNA Requirements Food and Nutrition Board recommends consumption of 800 mg day Deficiency seldom observed in man except in cases of long term consumption of antacids Most people consume far more than requirement Calcium and phosphorus tend to compete with each other for absorption Optimal absorption occurs at a calcium to phosphorous ratio of 1 1 If either compound is very much higher than the other the one at the lower concentration will not be well absorbed A food that contains equal amounts of both is optimal for absorption of both A diet very high in phosphorus will inhibit calcium absorption Cola drinks are fairly high in phosphorus A child who had a glass of milk immediately after drinking a cola would absorb less calcium than a child who consumed the milk an hour after the cola Magnesium Human body contains from 20 to 30 g half deposited in bones Remainder in soft tissues especially liver and muscle Approximately 35 of that in circulation is bound to protein Like calcium much of the magnesium in the body is found in bones While it serves many functions it is essential for enzymes that react with ATP If these reactions do not occur the body cannot use energy This is so important that a stockpile of magnesium is maintained It would be possible to have enzymes use