Category: Nutrition | Protein
Proteins are essential to the human body and its health, and it is necessary for us to eat certain foods to ensure that we get all the ‘essential’ nutrients that protein provides. Without these nutrients are bodies will not function properly. Fortunately, most people who eat a regular, healthy diet, will get enough protein in their diet, vegetarians must be more diligent in their diets, but they, too, should have no problem eating sufficient quantities.
What are Proteins?
Simply, they are large, complex molecules made up of hundreds or thousands of smaller units called amino acids. Amino acids are bound together in long chains, or necklaces, of which there are 20 different types. Depending how they are sequenced determines their structure and their specific function.
According to the U.S. National Library of Medicine, the 20 different amino acids are: alanine, arginine, asparagines, aspartic acid, cysteine, glutamic acid, glutamine, glycine – histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine.
Amino acids are organic molecules – they are made out of carbon, hydrogen, oxygen, nitrogen and sometimes sulphur.
To see examples of some of the functions of these amino acids – click here.
Of the 20 amino acids, there are 8 of them that are necessary to acquire through our diet.
How Much Protein Do We Need?
According to the U.S. Centers for Disease Control and Prevention, protein intake should be:
- Children ages 1 to 3 – 13 grams per day
- Children ages 4 to 8 – 19 grams per day
- Children ages 9 to 13 – 34 grams per day
- Girls ages 14 to 18 – 46 grams per day
- Boys ages 14 to 18 – 52 grams per day
- Women ages 19 to 70+ – 46 grams per day
- Men ages 19 to 70+ – 56 grams per day
- Pregnant or lactating (breastfeeding) women – about 71 grams per day
One gram of protein or carbohydrate contains 4 calories, while one gram of fat has 9 calories.
Sources of Protein
Good sources are meats, poultry, fish, legumes, milk and milk products, eggs, nuts and seeds, and some vegetables and fruits.
The best protein sources are the ones that are ‘complete’, complete means they have all the essential amino acids, such as red meat, poultry, seafood, eggs, and dairy,
For vegetarians or vegans there are a few non-animal sources that offer complete proteins, so it’s important to get your fill of soybeans, blue-green algae, hempseed, buckwheat, and quinoa.
NOTE: Vegetable protein is less well digested and utilized than animal protein. If the main protein source is from vegetables, 65 grams per day is recommended as compared with 45 grams per day when animal products provide the primary protein source.
The International Food Council Foundation found that a high percentage of women who eat more protein do not only avoid weight gain, but also report weight loss.
The Journal of Clinical Endocrinology and Metabolism, revealed that a calorie controlled diet lower in carbohydrates and higher in protein along with daily exercise has a significantly positive impact on bone health in overweight individuals as well as obese young women.
Protein | Centers for Disease Control and Prevention (CDC)
What are proteins and what do they do? | Genetics Home Reference, NIH
What are proteins? What is a protein? How much protein do I need? | Medical News Today (MNT)
David Zieve, MD, MHA, and David R. Eltz.”Protein in diet” U.S. National Library of Medicine, Department of Health and Human Services, National Institutes of Health. Accessed October 18th 2013.
What is Protein? | Utah State University Cooperative Extension