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Chapter 7

Water and Minerals

Learning Objectives

1. State the general characteristics of minerals

2. Identify the percentage of body weight made up of water

3. List the functions of water in the body 4. Identify the functions and food sources of

the major minerals and the trace minerals 5. Identify which minerals are most likely to

be deficient in the American diet

Learning Objectives (cont’d)

6. Discuss the nutrition of nuts and seeds and how to use them on the menu

7. Distinguish between different types of bottled waters

8. Explain how dietary supplements are regulated and labeled

9. Identify instances when supplements may be necessary

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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 through urine, skin, lungs, GI tract

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Food Facts: Bottled Waters

Artesian well water Mineral water Spring water Well water Purified water

Bottled water is regulated by the Food and Drug Administration.

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Calcium and Phosphorus

Used for building bones and teeth – found in hydroxyapatite

Calcium – Helps blood clot Helps muscles contract Helps nerves transmit

impulses May lower blood pressure

Phosphorus Involved in release of energy

from carb., fat, and protein Part of DNA Buffers acids and bases Activates some enzymes

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Sources of Calcium

Oxalic acid in leafy green vegetables and phytic acic found in whole grains

can decrease absorption of certain nutrients such as calcium and iron

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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

Fluid Compartments in the Body

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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 - bases 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

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

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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

Protein, carbohydrate, and fat metabolism DNA synthesis Wound healing Bone formation Development of sexual organs Taste perception

In addition, zinc is needed for general tissue growth and maintenance, vitamin A activity, protection of cell membranes from free radicals, 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

Hypothyroidism

Simple goiter

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

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Functions of Selenium

Important part of antioxidant enzymes that protect cells from free radicals

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 Energy metabolism

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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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: How Food Processing, Storage, Preparation, and Cooking Affect Vitamin and Mineral Content

1. Buy fresh, high-quality food2. Inspect fresh fruits and veggies for

appropriate color, size, and shape3. Store fresh fruits and veggies in the

refrigerator (except bananas, avocados, potatoes, and onions)

4. Minimize storage times and store canned goods in a cool place

5. Wrap up fresh fruits and veggies in the refrigerator to decrease exposure to air

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Food Facts: How Food Processing, Storage, Preparation, and Cooking Affect Vitamin and Mineral Content (cont’d.)

6. Wash fruits and veggies when ready to use

7. Cut vegetables up no more than necessary

8. Keep skins of fruits as much as possible

9. Steaming, microwaving, and stir-frying are good choices

10. Frying can destroy vitamins

11. Never use baking soda

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Food Facts: How Food Processing, Storage, Preparation, and Cooking Affect Vitamin and Mineral Content (cont’d.)

11. Broiled or roasted meats retain more B vitamins than meats that are braised or stewed

12. Use the cooking water from vegetables and the drippings from meat (after skimming off the fat) to prepare soup and gravy

13. Prepare foods close to the time of service

14. Don’t keep milk in glass containers

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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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