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Chapter 7

Water and Minerals

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Minerals

Major minerals Calcium Chloride Magnesium Phosphorus Potassium Sodium Sulfur

Trace Minerals Chromium Copper Fluoride Iodine Iron Manganese Molybdenum Selenium Zinc

Bioavailability

Toxicity

Cooking

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Functions of Water Medium for many metabolic

activities and also participates in some metabolic reactions.

Carries nutrients to the cells and carries away waste materials to the kidneys and out of the body in urine.

Needed in each step of the process of converting food into energy and tissue.

Maintains blood volume in your body.

Maintain normal body temperature.

Important part of body lubricants, such as cushioning joints and internal organs

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How Much Water is Enough?

AI for total water: Men: 3.7 liters/day

Women: 2.7 liters/day

Number of things, including thirst, work to keep body water content within limits.

You lose water thru urine, skin, lungs, GI tract.

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Calcium and Phosphorus

Used for building bones and teeth.

Calcium – Helps blood clot Helps muscles contract Helps nerves transmit

impulses May lower blood pressure

Phosphorus Helps release energy from C,

F, P Part of DNA Buffers acids and bases Makes some enzymes active

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Sources of Calcium

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Calcium: Deficiency and Toxicity

About 25-30% of calcium you eat is absorbed.

Deficiency

Calcium deficiency is a major contributing factor in osteoporosis.

Toxicity: UL is 2,500 milligrams

Amounts above UL can contribute to calcium deposits in kidneys and other organs

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Phosphorus

Widely distributed in foods

Rarely lacking in diet

Excellent sources: milk and milk products, meat, poultry, fish, eggs, legumes

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Functions of Magnesium

Many enzyme systems responsible for energy metabolism and making protein, fat, and nucleic acids.

Build bones and maintain teeth. Muscle relaxation, blood clotting, & nerve

transmission. Keep immune system working properly. May help regulate blood pressure.

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Magnesium is part of chlorophyll, the green pigment found in plants.

Lettuce

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Sources of Magnesium

Green leafy vegetables Potatoes Nuts (especially almonds and cashews) Seeds Legumes Whole-grain cereals Seafood

Magnesium occurs in most foods in small amounts.

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Magnesium: Deficiency & Toxicity

Deficiency is rarely seen, although dietary surveys suggest that many Americans don’t get enough.

Symptoms of deficiency: muscle twitching, cramps, weakness, depression, blood clots.

Very high doses can cause diarrhea and puts a stress on the kidneys (bad for elderly).

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Electrolytes

Sodium, potassium, and chlorides are referred to as electrolytes because when dissolved in body fluids, they separate into + or – charged particles called ions Sodium + found in fluid outside cells Chloride – found in fluid outside cells Potassium + found inside cells

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Functions of Electrolytes

Water balance Inside the cells Outside the cells In the blood

vessels

Acid-base balance

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Sources of Sodium

Salt – sodium chloride Processed foods:

Canned, cured, and/or smoked meats and fish such as bacon, ham

Many cheeses, esp. processed cheese

Canned veggies, etc. Frozen convenience foods Dried soup mixes Foods in brine

Certain seasonings: salt, soy sauce, Worcestershire sauce, etc.

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Sodium and Hypertension

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Functions of Potassium

Helps maintain water balance. Helps maintain acid-base balance. Assists in muscle contraction and normal

heartbeat. Assists in sending nerve impulses.

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Sources of Potassium

Widely distributed in plant and animal foods

(whole foods) Fruits (oranges &

bananas) Vegetables (potatoes) Milk and yogurt Legumes Meats

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Potassium: Deficiency & Toxicity

Deficiency is of concern because we don’t eat many whole foods. Can also result from dehydration, certain

diseases, or drugs (diuretics). Symptoms: muscle cramps, weakness,

nausea, abnormal heart rhythms.

Toxicity: can be toxic if too many supplements taken.

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Chloride

Maintains water balance. Maintains acid-base balance. Part of hydrochloric acid in the stomach. Helps remove carbon dioxide (waste product)

from the cells so the red blood cells can carry it to the lungs for disposal (exhaling).

Source: Salt (sodium chloride)

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Sulfur

Body doesn’t use sulfur by itself, but uses the nutrients it is found in, such as protein, thiamin, and biotin.

The protein in hair, skin, and nails is especially rich in sulfur.

No DRI – protein foods supply plenty of sulfur.

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Trace Minerals

Exciting area of research.

Many trace minerals are toxic at levels only several times higher than recommendations.

Trace minerals are highly interactive with each other.

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Functions of Iron

Key component of hemoglobin – a part of red blood cells that carries oxygen to body’s cells

Key component of myoglobin – a muscle protein that stores and carries oxygen that the muscles use to contract

Works with many enzymes in energy metabolism Used to make amino acids and certain hormones and

neurotransmitters Part of enzymes found in leukocytes (immune

system)

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Iron Absorption

About 15% of dietary iron is absorbed. More iron is absorbed if:

Body stores are low. Body needs to makes lots of RBCs

Heme iron (predominant form of iron in animal food) is absorbed and used twice as readily as iron in plant foods, nonheme iron.

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Iron Absorption (cont’d.)

Increase absorption of nonheme iron: Vitamin C Meat Poultry Fish

Decrease absorption of nonheme iron Calcium Substances found in

tea and coffee Oxalic acid (in

spinach) Phytic acid (in grain

fiber)

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Iron: Deficiency & Toxicity

Iron deficiency – a condition in which iron stores are used up

Iron-deficiency anemia –a condition in which the size and number of RBC are reduced, symptoms include: Fatigue, pallor, irritability Decreased immune function In kids – slow cognitive and social development During pregnancy – increased risk of premature

delivery, LBW babies Iron overload or hemochromatosis

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Zinc: Cofactor for Almost 100 Enzymes

Wound healing Bone formation DNA synthesis Protein, carbohydrate,

and fat metabolism Development of sexual

organs General tissue growth

and maintenance

Taste perception Vitamin A activity Protection of cell

membranes from free-radical attacks

Storage and release of insulin

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Sources of Zinc

Protein foods: shellfish, meat, poultry

Legumes Dairy foods Whole grains Fortified cereals

Absorbed better from animal sources.

Phytates decrease absorption.

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Zinc: Deficiency & Toxicity

Deficiency: more likely in pregnant women, the young and elderly, and vegetarians

Symptoms in adults: poor appetite, diarrhea, skin rash, hair loss.

Symptoms in children: growth retardation, delayed sexual maturation, poor appetite, decreased taste, delayed wound healing.

Toxicity: long-term intake of zinc over UL results in copper deficiency.

Avoid zinc supplements unless prescribed.

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Iodine

Required for normal thyroid gland functioning. Thyroid gland makes 2 hormones that

maintain a normal level of metabolism are essential to normal growth and

development are essential to normal body temperature are essential to protein synthesis and more.

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Sources of Iodine

Saltwater fish Grains grown in iodine-rich soil Iodized salt

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Iodine Deficiency

Hypothtroidism

Simple goiter

Cretinism – lack of thyroid secretion causes mental and physical retardation during fetal and later development

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Functions of Selenium

Important part of antioxidant enzymes that protect cells from free radicals.

Also essential for the normal functioning of the immune system.

Needed for normal functioning of thyroid gland.

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Sources of Selenium

Plant foods, varying on region

Meats and seafood Bread Nuts (Brazil nuts and

walnuts)

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Selenium: Deficiency & Toxicity

Deficiency: Keshan disease (enlarged heart) Deficiency is rare in US.

Toxicity: Moderate to high health risk associated with too much selenium.

Selenosis: High blood levels of selenium, symptoms include: Gastrointestinal upset Hair loss Mild nerve damage

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Fluoride

Fluoride strengthens the mineral composition of developing teeth in children and also strengthens bone.

Major source: Drinking water.

Toxicity: Fluorosis.

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Chromium

Works with insulin to transfer glucose and other nutrients from the bloodstream into the body’s cells.

Not known if chromium deficiency is a concern.

Not known whether chromium supplements are harmful.

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Sources of Chromium

Widely distributed throughout foods, but mostly in small amounts.

Good sources: Whole, unprocessed

foods, such as whole grain breads and cereals.

Wheat germ. Nuts.

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Copper

Important part of many enzymes. Aids in: Forming hemoglobin. Forming collagen. Normal functioning of nervous system,

immune system, and energy release.

Mostly in unprocessed foods: organ meats, seafood, nuts, seeds, milk, chicken, potatoes.

Deficiency is rare. Toxic at 4 times RDA.

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Manganese

Needed to form bone. Part of an enzyme that acts as an antioxidant. Needed as a cofactor for many enzymes

involved in CHO, fat, and protein metabolism.

Found in many foods, especially whole grains, dried fruits, nuts, leafy vegetables.

Too much or too little manganese is rare.

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Molybdenum

Cofactor for several enzymes. Found in legumes, meat, whole grains, and

nuts. No major concerns with deficiency or toxicity.

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Other Trace Minerals???

These minerals are essential to animals. Arsenic Boron Nickel Silicon Vanadium

Based on adverse effects noted in animal studies, UL have been set for boron, nickel, and vanadium.

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Osteoporosis

A disease characterized by: Low bone mass Structural deterioration of bone tissue Fragile bones Increased susceptibility to fractures of hip,

spine, and wrist

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Osteoporosis

Peak bone mass is attained during the early thirties. Bone is being constantly remodeled,and after the early thirties bone is broken down faster than it is deposited (especially during the five years after menopause for women due to estrogen decrease).

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Risk Factors for Osteoporosis

You can’t change these: Gender Age Body size Ethnicity Family history

You can change these: A diet low in calcium

and vitamin D Sedentary lifestyle Cigarette smoking Excessive use of

alcohol

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Prevention of Osteoporosis

The best approach to osteoporosis is prevention – taking in the AI for

calcium regular exercise consuming milk for

adequate vitamin D consuming moderate

amounts of alcohol avoiding smoking.

Medications, such as Fosamax, can increase bone density.

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Treatment of Osteoporosis

Proper nutrition – calcium and vitamin D Exercise Safety practices to prevent falls Possibly medications

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Ingredient Focus: Nuts & Seeds

Full of vitamins and minerals Fiber Protein A bit of fat – most of the fat (except in

walnuts) is monounsaturated Walnuts and flaxseed are rich on alpha-

linolenic acid (omega-3)

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Food Facts: Bottled Waters

Artesian well water Mineral water Spring water Well water Purified water

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Dietary Supplements

Dietary supplements are not drugs or replacements for conventional diets.

Role of FDA. Types of claims:

Nutrient claims Health claims Nutrition support

claims, which include “structure-function claims”

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Copyright ©2007 John Wiley & Sons, Inc.