Nutrition Basics
HISTORY OF NUTRITION
Nutritional discoveries from the earliest days of history have had a positive effect on our health and well-being. The word nutrition itself means “The process of nourishing or being nourished, especially the process by which a living organism assimilates food and uses it for growth and replacement of tissues”. Nutrients are substances that are essential to life, which must be supplied by food.
Today more than ever, obtaining nutritional knowledge can make a big difference in our lives. Air, soil, and water pollution in addition to modern farming techniques, have depleted our soils of vital minerals. The widespread use of food additives, chemicals, sugar and unhealthy fats in our diets contributes to many of the degenerative diseases of our day such as cancer, heart disease, arthritis and osteoporosis. Here is a brief history of the science that offers the hope of improving our health naturally.
400 B.C. Hippocrates, the “Father of Medicine”, said to his students, “Let thy food be thy medicine and thy medicine be thy food”. He also said “A wise man should consider that health is the greatest of human blessings”.
400 B.C. Foods were often used as cosmetics or as medicines in the treatment of wounds. In some of the early Far-Eastern biblical writings, there were references to food and health. One story describes the treatment of eye disease, now known to be due to a vitamin A deficiency, by squeezing the juice of liver onto the eye. Vitamin A is stored in large amounts in the liver.
MACRONUTRIENTS
The main function of macronutrients is to provide energy, counted as calories. While each of the macronutrients provides calories, the amount provided by each varies:
Carbohydrates provides 4 calories per gram
Protein provides 4 calories per gram
Fat provides 9 calories per gram
Example: If a Nutrition Facts label of a given food indicates 12 g of carbohydrate, 2 g of fat, and 0 g of protein per serving, the food then has 12g carbohydrate x 4 calories = 48 calories þ 2 g fat x 4 calories = 8 calories for a total of 48 þ 8 calories = 56 calories per serving).
Macronutrients also have specific roles in maintaining the body and contribute to the taste, texture and appearance of foods, which helps to make the diet more varied and enjoyable.
MICRONUTRIENTS
Micronutrients are what are commonly referred to as “vitamins and minerals.” Micronutrients include such minerals as flouride, selenium, sodium, iodine, copper and zinc. They also include vitamins such as vitamin C, A, D, E and K, as well as the B-complex vitamins.
As mentioned, micronutrients are different from the macronutrients protein, carbohydrate and fat, and micronutrients are called “micro”-nutrients because your body needs only very small quantities of them for survival. However, if your body doesn’t get the small quantities of micronutrients that it needs, serious health problems can result.
Micronutrients are vital to the proper functioning of all of your body’s systems. Sodium, for instance, is responsible for maintaining the proper fluid balance in your body; it helps fluids pass through cell walls and helps regulate appropriate pH levels in your blood. Here are some of the ways that other micronutrients help maintain your body’s systems:
Manganese promotes bone formation and energy production, and helps your body metabolize the macronutrients, protein, carbohydrate and fat.
Magnesium helps your heart maintain its normal rhythm. It helps your body convert glucose (blood sugar) into energy, and it is necessary for the metabolization of the micronutrients calcium and vitamin C.
Iron helps your body produce red blood cells and lymphocytes.
Iodine helps your thyroid gland develop and function. It helps your body to metabolize fats, and promotes energy production and growth.
Chloride helps regulate water and electrolytes within your cells, as well as helping to maintain appropriate cellular pH levels.
CALORIE: KILOCALORIE –UNIT OF ENERGY
Calories are just a measurement tool, like inches or ounces. They measure the energy a food or beverage provides — from the carbohydrate, fat, protein, and alcohol it contains.
Calories are the fuel you need to work and play. You even need calories to rest and sleep! Foods and beverages vary in how many calories and nutrients they contain. When choosing what to eat and drink, it’s important to get the right mix, enough nutrients, but not too many calories.
WHAT ARE CARBOHYDRATES?
Your body uses carbohydrates (carbs) to make glucose, which is the fuel that gives you energy and helps keep everything going. Your body can use this glucose immediately, or store it in your liver and muscles, for a later time when it is needed for energy.
You can find carbohydrates in the following:
Fruits
Vegetables
Breads, cereals, and other grains
Milk and milk products sugar-sweetened
Foods containing added sugars (e.g., cakes, cookies, and beverages).
There are two main types of carbohydrates, complex carbohydrates and simple carbohydrates.
COMPLEX CARBOHYDRATES
Starch and dietary fiber are the two primary types of complex carbohydrates. Starch must be broken down through digestion before your body can use it as a glucose source.
Quite a few foods contain starch and dietary fiber such as breads, cereals, and vegetables:
Starch is in certain vegetables (i.e., potatoes, dry beans, peas, and corn).
Starch is also found in breads, cereals, and grains.
Dietary fiber is in vegetables, fruits, and whole grain foods.
DIETARY FIBER
You may have seen dietary fiber on the label listed as soluble fiber, or insoluble fiber.
Soluble fiber is found in the following:
Oatmeal
Oat bran
Nuts and seeds
Most fruits (e.g., strawberries, blueberries, pears, and apples)
Dry beans and peas
Insoluble fiber found in the following:
Whole wheat bread
Barley
Brown rice
Couscous
Bulgur or whole grain cereals
Wheat bran
Seeds
Most vegetables
Fruits
FATS & CHOLESTEROL
What counts as fat? Are some fats better than other fats? While fats are essential for normal body function, some fats are better for you than others. Trans fats, saturated fats, and cholesterol are less healthy than polyunsaturated and monounsaturated fats.
How much total dietary fat do I need?
The Dietary Guidelines for Americans 2010 recommend that Americans:
Consume less than 10% of calories from saturated fats.
Replace solid fats with oils when possible.
Limit foods that contain synthetic sources of trans fatty acids (such as hydrogenated oils), and keep total trans fatty acid consumption as low as possible.
Eat fewer than 300 mg of dietary cholesterol per day.
Reduce intake of calories from solid fats.
WHAT IS PROTEIN?
Proteins are part of every cell, tissue, and organ in our bodies. These body proteins are constantly being broken down and replaced. The protein in the foods we eat is digested into amino acids that are later used to replace these proteins in our bodies.
Protein is found in the following foods:
Meats: Poultry, Seafood, Beef, Lamb, Port etc.
Legumes (dry beans and peas)
Tofu
Eggs
Nuts and Seeds
Milk and Milk products
Grains, some Vegetables, and some Fruits (provide only small amounts of protein relative to other sources)