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OVERVIEW
Vitamins are required to maintain health, but we must eat them in our
diet, since we can't make them. Vitamins are generally divided into two
categories, the fat soluble and the water soluble vitamins. The fat
soluble vitamins, Vitamins A, D, E and K are stable to heat, light, and
air, but they require fat in the diet to be absorbed and transported.
Conversely, the water soluble vitamins, Vitamin C and the B complex, are
NOT stable to heat, light or air, and they are readily absorbed,
with/without fat in the diet.
Which vitamins are of major concern for backpackers?
Both Vitamin C and Vitamin E. Vitamin C because of its instability in air/light. And Vitamin E because hikers need more and may be getting less, due to their change in dietary habits. The requirement for other vitamins does not vary significantly from the normal recommendation and no benefit will accrue by eating excessive amounts. Excess water soluble vitamins will simply wash out in the urine. Excessive intake of the fat soluble Vitamins A and D can kill you--or at least cause severe problems. So DON'T exceed the RDA if you decide to supplement your diet with a pill. (A "One-A-Day" provides the RDA.) For a summary of the vitamins and what they do, see Table 8. Vitamins -- RDA & Function.
Why is Vitamin C of special concern for long distance hikers?
Vitamin C is critical for building healthy connective tissue (muscles, ligaments, blood vessel walls--everything that is keeping you going, mile after mile) and for preventing oxidative damage in the water-soluble compartments of your body. It is also beneficial in assisting in iron absorption and utilization. So where does it come from? Normally, fresh fruits, fruit juice and vegetables. But because Vitamin C is NOT stable to heat, light and air, dried fruits and dried vegetables have lost over 90% of their natural Vitamin C. Since fresh oranges are not likely to be included in your menu, and wild berries along the trail are not to be depended upon, you will have to make a conscious effort to find Vit. C fortified foods/drink mixes (Spiced Cider, Tang, Instant Breakfast, some cold cereals--read the labels), or take a supplement (a "One-A-Day") to get the recommended 60 mg/day.
What is the function of Vitamin E?
Vitamin E is an antioxidant in cell membranes and organelles. It is of major concern because exercise may promote more free radical damage within the tissue and Vit. E protects cell membranes from oxidative damage. Since you may need more on the trail, look for good sources of Vitamin E: vegetable or olive oil, nuts, whole grain cereals, wheat germ, seeds, peanut butter. All you need is 10-15 mg/day, so it only takes 3-4 servings/day of Vitamin E-rich foods each day.
How can I prevent oxidation of my food?
Dried food is generally safe food. It will keep for weeks without refrigeration . However, the food can/does become damaged by exposure to oxygen (air). Before you can taste, smell or see the damage, oxygen will be at work "oxidizing" your food. Oxidative damage goes on whether or not your food is refrigerated or nonrefrigerated, dried or undried. Fortunately, naturally occurring antioxidants provide protection from oxidized products. But you can assist the vitamins by intervening to prevent some damage.
First, wrap individual portions in sandwich bags, then fill a
ziplock baggie with multiple portions. For example, when instant rice is
on sale and you buy a large package, then portion out 1 Cup instant rice, a dash
of salt or Butter Buds in each of 15-20 sandwich bags, ready for the next
adventure. Stack about 5 bags in a ziplock baggie (label it) and then store it
in a dry place (5 gallon bucket with a lid) or the freezer. By filling the bag
with food, you exclude air (which contains oxygen). Remove as much
remaining air as possible by squeezing the filled baggie. For the truly zealous,
use a plastic straw to suck out the excess air as you zip the baggie closed. Or
you can buy a plastic bag sealing device (eg., Seal A Meal) at most major
department stores.
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Table 8. VITAMINS -- RDA & FUNCTION
| VITAMINS | RDA male/female |
FUNCTION | TRAIL FOOD SOURCES | PRECAUTIONS |
|---|---|---|---|---|
| FAT SOLUBLE | ||||
| A, retinol et al. (RE) | 1000/800 | Maintains healthy skin and bones, Enhances visual perception (night vision) |
Carrots, fortified cereals, eggs, margarine, vegetables | Toxic in excess |
| D, cholecalciferol (IU) | 200 / 200 | Enhances calcium absorption for bone & tooth formation | Sunshine | Toxic in excess |
| E, tocopherol (mg) | 10 / 8 | Antioxidant in cell membrane protecting cells from damage | Vegetable oil, margarine, nuts & seeds | -- |
| K, menoquinone (ug) | 80 / 65 | Blood coagulation and bone formation | Microbes in the gut, Vegetables | -- |
| WATER SOLUBLE | ||||
| B1, thiamin (mg) | 1.5 / 1.1 | --> Energy from carbohydrates & fats, (removes CO2) | Fortified cereals, grains, beans, seeds | -- |
| B2, riboflavin (mg) | 1.7 / 1.3 | -->Energy from carbohydrates & fats (transports Hydrogen -->Energy) | Fortified cereals, grains, milk, meat, nuts | -- |
| Niacin (mg) | 19 / 15 | -->Energy from carbohydrates & fats (transports Hydrogen -->Energy) | Fortified cereals/drinks, meat, fruits, vegetables | -- |
| Pantothenate (mg) | 7 / 7* | -->Energy from carbohydrates, fats & proteins (transports Acetyl units) | Fortified cereals, grains, milk, nuts -- everywhere! | -- |
| B6, pyridoxine (mg) | 2.0 / 1.6 | Critical in utilizing proteins and glycogen to --> glucose & amino acids | Fortified cereals, beans,meat, milk, nuts | -- |
| Biotin (ug) | 100 / 100* | --> glucose by recycling lactic acid, glycerol, alanine (gluconeogenesis) | Eggs, beans, vegetables & gut microbes | -- |
| Folic acid (ug) | 200 / 180 | -->DNA for growing cells, especially red blood cells | Fortified cereals/drinks, beans,vegetables | -- |
| B12, cobalamin (ug) | 2 / 2 | -->DNA and maintains the nervous system | Meat, dairy, eggs | -- |
| C, ascorbic acid (mg) | 60 / 60 | -->collagen for muscles & ligaments, Antioxidant, favors Iron absorption | Fortified drinks, fresh fruits or vegetables | -- |
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*Maximum recommended value for adult male or female when a range is given.
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