Introduction
Among the achievements for which this last century is surely remembered is the discovery of vitamins. For hundred of years people noticed that certain foods seemed to prevent diseases, but the first vitamin was isolated in a lab only in 1911. Now 13 vitamins are known, although we still have much to learn about the functions of these chemicals. In the last decade alone, hundreds of scientific studies have found that vitamins play a much larger role in health than was ever dreamed.
Taking daily multivitamin and mineral supplements cannot turn a poor diet into a healthy one. Today's session will focus on the importance of food versus supplements in the diet as well as circumstances when supplementation may be necessary. We will also take an in-depth look at a few vitamins and minerals.
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Goal
To educate university/college students on the functions and food sources of various vitamins and minerals in the Canadian diet.
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Educational Outcomes
At the end of this session students will have gained an understanding of:
- The advantages of relying on food to meet vitamin and mineral needs.
- The functions and food sources of various vitamins and minerals necessary in the Canadian diet.
- Circumstances which warrant the use of vitamin and mineral supplements.
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Activities |
Approximate Time |
| Introduction |
5 Minutes |
| Text |
10 - 15 Minutes |
| Exercise |
10 - 15 Minutes |
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Suggested Background Reading for Presenters
Using the Food Guide, Health and Welfare Canada. (Enclosed)
New and Revised Vitamin Issues of the 90's: 99 Questions & Answers, Roche. (Enclosed)
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Materials
- Text
- Overheads
- PENS: Vitamins and Minerals
- Key Nutrients in Canada's Food Guide to Healthy Eating
- Who needs supplements?
- Iron
- Iron (Continued)
- Calcium
- Zinc
- Vitamin B12
- Folate
- Vitamin A
- Answers to Vitamin and Mineral Quiz
- Suggested handouts
- Nutrient Functions and Sources
- Vitamin Information: Vitamins and their Role in Nutrition, Hoffmann-La Roche Limited, 1994.
- Choices: On Safari Through the Vitamin Jungle, Dietitians of Canada, 1992.
- Nutrition Matters: Supplements. Do we Really Need Them? Middlesex- London Health Unit, 1994.
- Vitamin and Mineral Quiz
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What are vitamin?
Vitamins are organic (contain carbon) substances required to regulate the functioning of cells. They are essential to life. They take part in all biological process such as promoting good vision, forming normal blood cells, creating strong bones and teeth, and ensuring the proper function of the heart and nervous system. While vitamins supply no energy, they do aid in the conversion of foods into energy.
There are 13 essential vitamins which fall into two categories: fat-soluble (vitamins A, D, E and K) and water-soluble vitamins (the B vitamins and vitamin C). This distinction is important because the body stores fat-soluble vitamins in the liver and fatty tissues for relatively long periods, but it stores the water-soluble vitamins for only a short time. In general, you have to consume vitamins - the body cannot manufacture most of them.
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What are minerals?
Minerals are the simplest of the nutrients. They are inorganic - they contain no carbon. Some 16 minerals are know to be essential in human nutrition; others are sill being studied. People consume varying amounts of most minerals daily, from nearly a gram in the case of calcium to a million times less. Some minerals may be put together into orderly arrays in such structures as bones and teeth - but only with the help of the body's metabolic machinery. Minerals in the fluids of the body influence the properties of those fluids, but they are not metabolized and like vitamins, they do not yield energy.
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The Importance of Food Versus Supplements
Most people do not need a daily multivitamin and mineral supplement, although millions of Americans take one. Relying on food to meet your vitamin and mineral needs has many advantages:
- A high concentration of vitamin and mineral supplements in the intestine may interfere with the absorption of other nutrients.
- Excess fat soluble vitamins ( A, D, E and K), will be stored in your body fat, and can build to toxic levels over a period of time.
- Vitamins, minerals and other nutrients in foods help to provide balanced nutrition. For example, 6 ounces of orange juice contains 60g of vitamin C, but it also contains over 100 other beneficial substances. Mother nature has put them there to balance each other out. Vitamin supplements, whether they be single or multi-vitamin pill, do not provide this same delicate balance.
- Vitamin supplements can give a person a false sense of security promoting poorer eating habits.
- It is almost impossible to overdose on vitamins and minerals from food.
- Food tastes great, satisfies our hunger and is far less expensive than a supply of vitamin supplements.
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Enjoy a Variety of Foods
Canada's Guidelines For Healthy Eating states that we should enjoy a variety of foods from all four food groups as well as from within each group. As they say, "variety is the spice of life". Different tastes, textures and colours add to the excitement and pleasure of eating. Variety in food choices is also necessary because no food group can supply all the different nutrients our bodies need on a daily basis. Each food group is essential because it provides its own set of nutrients.
(Overhead 2)
Foods within each food group provide different amounts and types of nutrients. For example, unrefined grain products contain more fibre and zinc than refined ones. Enriched cereal and pasta contain more iron and B vitamins than unenriched products. Looking at the milk products, one will find that all fluid milk contains almost equal amounts of vitamins A and D whereas milk products like yogurt contain no added vitamin D. Cottage cheese contains lower amounts of calcium than other milk products.
Overall, your body needs more than fifty different nutrients. These nutrients can be readily found in the foods we eat. For healthy individuals, supplements are generally not necessary, if a wide variety of foods from all four food groups are consumed. It is also much safer to get your nutrients from food rather than from drugs. Large quantities of vitamin and mineral supplements are expensive and can have dangerous side effects on long term health. For example, large doses of the fat soluble vitamin A can be toxic over time!
There are a few cases where supplements are necessary, but as a general rule, it is always a good idea to consult with your family doctor or a dietitian before taking supplements.
(overhead 3)
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Special circumstances under which supplements are recommended
- During pregnancy. Pregnant women require more folacin, iron and calcium than non pregnant women.
- For children who do not drink fluoridated water, a fluoride supplement is recommended.
- Persons following a strict vegetarian or vegan diet may need calcium, iron and/or vitamin B12 supplements.
- Persons with true allergies to foods like milk and wheat. These foods contribute many essential nutrients to the diet and it is therefore very important that they discuss possible deficiencies with their Doctor or Dietitian.
- Women who experience very heavy periods may require an iron supplement.
- Heavy drinkers and/or smokers may also require additional vitamin B and vitamin C.
- Persons on restricted therapeutic diets may potentially become deficient in several nutrients and should seek the advise of a Doctor or Dietitian.
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Vitamins and Minerals
There are many vitamins and minerals required in the Canadian diet. Today, we will focus on only a few but this does not imply that these are the only vitamins which are important. All vitamins and minerals are essential for a healthy lifestyle. We have chosen to discuss the following nutrients because, in our society, they have been known to be most problematic.
(Review Overheads 4 - 10 - IRON, CALCIUM, ZINC, VITAMIN B12, FOLATE and VITAMIN A)
[Allow participants a few minutes to complete the quiz. Discuss the answers. (Overhead 11)]
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Who Needs Supplements?
- Pregnant Women - Folacin, Iron and Calcium
- Children who do not drink fluoridated water - fluoride
- Strict Vegetarians or Vegans - Calcium, Iron, Vitamin B12
- Persons with allergies to some foods (e.g., Milk and Wheat) - These foods contribute many essential nutrients to your diet.
- Women who experience heavy periods - Iron
- Heavy drinker and/or smoker - may interfere with nutrient absorption.
- Persons on restricted therapeutic diets
Remember: It is very important to consult a professional before taking supplements!
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VITAMIN AND MINERAL QUIZ
- The best sources of daily requirement for vitamins and minerals is foods in the usual diets.
T or F
- Which of the following vitamins is NOT fat-soluble:
A) vitamin C
B) vitamin D
C) vitamin A
D) vitamin E
- Vitamin supplements are not recommended without the advice of a professional because:
A) They can be expensive and often times unnecessary.
B) Pills cannot provide the same balance of nutrients as can foods.
C) They may cause people to ignore their diet.
D) All of the above.
- Fat-soluble vitamins are vitamins which:
A) Help digest fat.
B) Require fat in order to be absorbed and stored.
C) Have fatty acid chains in their chemical structure.
D) All of the above.
- Variety is important in our diets because:
A) Variety is the spice of life.
B) Each food group provides different nutrients.
C) The meat group provides us with calcium, whereas the vegetables and fruit group does not.
D) If there is no variety, then people become bored with food, lose their appetite and increase their risk of nutrient deficiencies.
- Which food is NOT abundant in vitamin A?
A) Carrots
B) Whole wheat bread
C) Apricots
D) Margarine
- Which of the following situations most likely would not require supplementation?
A) Individuals on strict vegetarian or vegan diets.
B) Individuals on restricted, therapeutic diets
C) Individual with allergies to foods like milk and wheat.
D) Athlete.
- To increase the amount of iron absorbed by your body, it is best to eat iron rich foods with a source of what?
a) Vitamin A
b) Vitamin C
c) Zinc
d) None. You have no control over iron absorption
- Beans, sunflower seeds, Brussels sprouts and spinach are all sources of which nutrient?
A) Iron
B) Zinc
C) Vitamin C
D) Vitamin B12
- Which nutrient will help blood to clot, muscles to contract and nerves and heart to work properly?
A) Zinc
B) Vitamin K
C) Calcium
D) Vitamin B12
ANSWERS
- TRUE
- A) Vitamin C
- D) All of the above
- B) They are soluble in fat and require it to be absorbed
- B) Each food group provides different nutrients.
- B) Whole wheat bread
- D) If you are an athlete.
- B) Vitamin C
- A) Iron
- C) Calcium
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IRON
Function
- Acts as a building block for red blood cells which help carry the oxygen we breath and deliver it to every cell in our body
- Helps to increase resistance to infection
Types
- Heme Iron
- Found exclusively in foods of animal origin (i.e., pork, beef, chicken, liver, turkey, sardines)
- Absorbed well by the body
-
Non Heme Iron
- Found primarily in foods of plant origin
(i.e., beans [kidney, navy, lima], peas [split, chick], sunflower seeds, almonds, lentils, Brussels sprouts, spinach, prunes, dates, cream of wheat, enriched cereals, brown rice)
- Not absorbed as well by the body
Absorption Enhancers
- Eating iron rich foods with a source of Vitamin C (i.e., orange juice, strawberries, broccoli, cantaloupe, kiwi), will increase the amount of iron absorbed by the body
Absorption Inhibitors
- Non-herbal teas and coffee contain substances that can bind iron making it unavailable for use by the body
Deficiencies
- Too little dietary iron means less oxygen to the cells resulting in less energy, tiredness and irritability
- Iron deficiency is one of the most common nutritional deficiencies in females, female athletes and growing children
Recommended Nutrient Intake (RNI)
- 9 mg/day - men (Age 19 - 24)
- 13 mg/day - women (Age 19 - 24)
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CALCIUM
Function
- Forms and maintains healthy bones
- Helps blood to clot, muscles to contract, and nerves and heart to function properly
Sources
- Milk and Milk Products (yogurt, cottage cheese)
- Sardines and Salmon with the bones
- Dark Green Leafy Vegetables (Kale, Broccoli, Spinach, Swiss Chard)
- Tofu and Soy Products enriched with Calcium
Deficiency
- Osteoporosis (Post-menopausal women)
(It is very important, to consume adequate amounts of calcium at a young age to prevent this crippling disease in old age.)
Recommended Nutrient Intake (RNI)
- 800 mg/day - men (Age 19 - 24)
- 700 mg/day - women (Age 19 - 24)
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ZINC
Function
- Important in fetal growth
- Promotes normal growth and development
- Assists in wound healing
Sources
- Oysters
- Meat, Fish and Poultry
- Whole Grains (Breads, Cereals, Rice, Bulgur, Barley)
- Legumes (Peas, Beans, and Lentils)
Recommended Nutrient Intake (RNI)
- 12 mg/day - men (Age 19 - 24)
- 9 mg/day - women (Age 19 - 24)
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Vitamin B12
Function
- Essential for the maturation of red blood cells and DNA synthesis
- Essential for maintaining mental function
Sources
- Foods of animal origin only
- Liver, Kidney, Meat, Shellfish, Sardines, Salmon, Herring, Egg Yolk, Milk Products
Deficiency
- Rare
- Most common in strict vegans where all foods of animal origin are eliminated (Pernicious anemia)
Recommended Nutrient Intake (RNI)
- 2 ug/day - men & women ages 19 - 24
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FOLATE
Function
- Aids in the formation of red blood cells and in protein metabolism
- Very important during the 1st trimester of pregnancy to prevent Neural Tube Defect and Spinal Bifida
Sources
- Dark Green Leafy Vegetables
- Oranges, Orange Juice, Bananas and Strawberries
- Wheat Germ, Fortified Breads and Cereals
Recommended Nutrient Intake (RNI)
- 210 ug - men (Ages 19 - 24)
- 175 ug - women (Ages 19 - 24)
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VITAMIN - A
Function
- Promotes healthy eye tissue
- Prevents night blindness (adaptation to dim light)
- Reduces infections by maintaining the integrity of the skin and other membrane
Sources
- Liver, Eggs, Fish & Fish Oil
- Dark Green Leafy Vegetables and Yellow and Orange Fruits and Vegetables
- Dairy products (Cheese and Milk)
- Butter and Margarine
Recommended Nutrient Intake (RNI)
- 1000 RE/day - men ages 19 - 24
- 800 RE/day - women ages 19 - 24
(RE = Retinol Equivalent)
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