Major Minerals

1. Major Minerals Chapter 11

2. Major Minerals • A major mineral is required in the diet and present in the body in large amounts compared with the trace minerals. • Minerals are inorganic elemental atoms or ions. • Minerals are not changed during digestion or when the body uses them.

3. Major Minerals • Minerals are not destroyed by heat, light, or alkalinity. • Some minerals assist enzymes. • Some minerals have structural roles.

4. Minerals In the Human Body

5. Minerals in Foods • Foods from both plants and animals are sources of minerals. • Animal tissues contain minerals in the proportions that animals need.

6. Minerals in Foods • The mineral content of plants can vary dramatically depending upon the minerals in the soil where the plant is found. • The maturity of the vegetable, fruit, or grain can affect the mineral content.

7. Mineral Bioavailability • The GI tract absorbs a much smaller proportion of minerals than vitamins. • Once absorbed, excess minerals are difficult for the body to flush out. • The body adjusts mineral absorption in relation to needs.

8. Mineral Bioavailability • Some minerals compete for absorption sites. Megadosing with one mineral can impede absorption of another. • High-fiber diets reduce absorption of iron, calcium, zinc, and magnesium. • Phytate (a component of whole grains) binds minerals and carries them out of the intestine unabsorbed. • Oxalate (found in spinach and rhubarb) binds calcium, reducing its absorption.

9. Mineral Bioavailability

10. Sodium • Sodium (Na) is an essential nutrient. • Sodium is a component of sodium chloride (table salt). • Sodium in the diet is essential for normal body function, but we shouldn’t eat too much salt. • Major extracellular cation.

11. Sodium Functions • Fluid balance. Maintains proper body water distribution and blood pressure. • Nerve transmission and muscle function. • Control’s the body’s acidity.

12. Sodium Food Sources and Recommended Intake • Limit to 2,300 milligrams / day (DV) • Processed foods contribute the most sodium. • Table salt contributes some. • Sauces, pickled foods, salty meats, cheese, salted snack foods, bouillon cubes, canned and instant foods, and seasonings based on salt can all be high sources. • The GI tract absorbs nearly all dietary sodium. • The kidneys excrete excess.

13. Sources of Dietary Sodium

14. Hyponatremia • Hyponatremia – abnormally low sodium concentrations in the blood due to excessive excretion of sodium (by the kidenys), prolonged vomiting, or diarrhea. • Replacement of water without sodium.

15. Hyponatremia • Symptoms of hyponatremia resemble dehydration. • Treatment involves replacement of fluids and minerals through liquids and foods or intravenous solutions if necessary.

16. Hyponatremia • Severe hyponatremia causes extracellular fluid to move into cells, causing them to swell. • Brain cells swell – headache, confusion, seizures, coma. • Cancer, kidney disease, and heart disease can cause hyponatremia.

17. Hypernatremia • Hypernatremia – abnormally high sodium concentrations in the blood due to increased kidney retention of sodium or rapid ingestion of large amounts of salt. • Hypervolemia – an abnormal increase in the circulating blood volume.

18. Hypernatremia • Hypervolemia leads to edema (swelling) and a rise in blood pressure. • A healthy person with normal kidneys and ample water intake rapidly excretes excess sodium.

19. Hypernatremia • Hypernatremia is seen in patients with congestive heart failure and kidney disease. • Eating too much sodium over a long period of time can contribute to hypertension (high blood pressure) in some people. • Excess dietary sodium can contribute to osteoporosis by increasing calcium loss in the urine.

20. Exercise and Sodium Sensitivity • A recent study sought to examine if aerobic exercise training in older people with hypertension changes sodium sensitivity with individuals switching from sodium sensitive to sodium resistant. • The study was validated and shows that that aerobic training in older hypertensive people can alter blood pressure sensitivity.

21. ADA Dietary Guidelines for Americans • Consume less than 2,300 mg (approximately 1 teaspoon of salt) of sodium per day. • Choose and prepare foods with little salt. At the same time, consume potassium-rich foods, such as fruits and vegetables. • Key recommendations for Specific Population Groups: Individuals with hypertension, blacks, and middle-aged and older adults. Aim to consume no more than 1,500 mg of sodium per day, and meet the potassium recommendation (4,700 mg/day) with food.

22. Potassium • Major intracellular cation. • If people with hypertension eat a diet rich in potassium containing foods (fruits and vegetables), their blood pressure often improves.

23. Potassium Functions • Muscle contractions • Transmission of nerve impulses • Helps regulate blood pressure

24. Potassium Food Sources and Recommended Intake • Fresh vegetables and fruits. • Especially potatoes, spinach, melons, and bananas. • Fresh meat, milk, coffee, and tea also contain some potassium.

25. Food Sources of Potassium

26. Hypokalemia • Hypokalemia – low levels of blood potassium. • Low intake can disrupt acid-base balance, contribute to bone loss and kidney stones. • Severe deficiency results from potassium depletion (excessive losses). • Prolonged vomiting, chronic diarrhea, laxative abuse, use of diuretics. • Risk factor for hypertension.

27. Hypokalemia • People with poor diets, such as alcoholics and individuals who suffer from anorexia nervosa or bulimia nervosa, are at highest risk of potassium deficiency. • Athletes doing physical labor in high temperatures have high water losses, so they also risk potassium deficiency.

28. Hypokalemia Symptoms • Muscle weakness • Loss of appetite • Confusion • Severe or rapid potassium depletion can disrupt heart rhythms

29. Hyperkalemia • Hyperkalemia – abnormally high blood potassium. • Malfunctioning kidneys or an excess of intravenous potassium can cause hyperkalemia. • Hyperkalemia can slow and eventually stop the heart.

30. Banana Facts • You may know that bananas are high in potassium, but did you also know that they have an unusually high-carbohydrate content? • Before ripening, a banana is almost entirely starch. After ripening, certain varieties are almost entirely sugar—as much as 20 percent by weight.

31. Chloride • Chloride (Cl-) – anion in table salt. • Chlorine (Cl2) – poisonous gas – highly reactive, used to treat water to kill bacteria and other pathogens. • Chloride is a major extracellular anion.

32. Chloride Functions • Fluid balance. • Combines with H+ to form HCl (hydrochloric acid in the stomach). • White blood cells use chloride to kill invading bacteria. • Assists in the transmission of nerve impulses.

33. Chloride Food Source • Most of our chloride comes from salt. • The kidneys secrete excess chloride and some is lost in sweat. • The only known cause of high blood chloride is severe dehydration.

34. Hypochloremia • Vomiting removes hydrochloric acid from the stomach. • Frequent vomiting (bulimia nervosa) can cause a chloride deficiency. • Frequent vomiting with inadequate fluid and mineral consumption can lead to dehydration and metabolic alkalosis (high blood pH).

35. Hypochloremia • Metabolic alkalosis – abnormal pH of body fluids usually caused by significant loss of acid from the body or increased levels of bicarbonate. • Causes abnormal heart rhythm, substantial drop in blood flow to the brain, decreased oxygen delivery to the tissues, abnormal metabolic activity. • 5 percent rise in pH can be fatal.

36. Calcium • About 1.5 to 2% of total body weight. • Essential for healthy bones and teeth.

37. Calcium Functions • Bones and tooth structure (99%) of calcium. • Remaining 1% in blood and soft tissues. • Muscle contraction. • Nerve impulse transmission. • Blood clotting. • Cell metabolism.

38. Calcium Functions

39. Bone Structure • Bone is made up of cells and an extracellular matrix. • Osteoblasts and osteoclasts continually remodel our bones.

40. Bone Structure • Osteoblasts secrete the collagen protein matrix that forms the framework. • Minerals in the form of hydroxyapatite (calcium and phosphorus) surround the collagen fibers. • We achieve peak bone mass at around 30 years of age.

41. Calcium Food Sources • Dairy products. • Green leafy vegetables such as spinach have high levels of calcium, but it is mostly bound to oxalate and therefore cannot be absorbed. • Chinese cabbage, kale, and turnip greens have significant amounts of bioavailable calcium. • Some food products are fortified with calcium.

42. Calcium Recommended Intake • Adequate Intake (AI) for adults 19 to 50 – 1,000 milligrams per day. • AI for adults aged 51 and older – 1,200 milligrams per day. • AI for adolescents 9 to 18 – 1,300 milligrams per day.

43. Regulation of Blood Calcium • Circulating blood calcium performs many essential functions; therefore, the body will demineralize bone tissue to prevent even minor changes in blood calcium. • Three hormones regulate blood calcium: • Calcitriol (active form of vitamin D) • Parathyroid hormone • Calcitonin

44. Regulation of Blood Calcium • These hormones control intestinal absorption of calcium, bone calcium release, and calcium excretion by the kidneys. • Inadequate calcium intake, high sodium intake, excess caffeine, and other diuretics can effect calcium balance by altering the excretion of calcium in the urine.

45. Vitamin D (calcitriol – active form) • Increases absorption of calcium into the intestine. • Increases the production of calcium binding proteins in the small intestine.

46. Parathyroid Hormone • Parathyroid Hormone (PTH) is secreted when plasma calcium levels fall too low. • PTH activates osteoclasts, which break down bone and release calcium and phosphorus into the blood. • Increases kidney reabsorption of calcium. • Increases phosphorus excretion. • Stimulates calcitriol production.

47. Calcitonin • The thyroid gland secretes calcitonin when plasma calcium is too high. • Acts in opposition to PTH. • Weak effects on blood calcium. • Inhibits formation and activity of osteoclasts. • High calcitonin concentrations decreases PTH production and thus decreases calitriol production.

49. Calcium Absorption • Between 25 to 75 percent of dietary calcium. • High during pregnancy and infancy. • Low during old age. • Requires adequate levels of vitamin D. • Inversely related to calcium intake.

50. Calcium Absorption • Phytates (in nuts, seeds, grains) decrease absorption. • Oxalates decrease absorption. • High levels of phosphorus and magnesium decrease absorption. • Wheat bran decreases absorption (other dietary fibers do not seem to decrease absorption). • Low estrogen levels after menopause decrease absorption. • Calcium from supplements taken between meals and at lower doses of 500 milligrams or less assists in absorption.