Protein

Protein in the body

The body's primary building block for muscle, bone, skin, hair, and many other tissues is protein. Over 10,000 different proteins are found and needed in the body for maintaining life. In fact, after water has been excluded 75 percent of your body weight consists of protein. Proteins play many important roles in the body including the structure of enzymes; these are important proteins that help reactions occur in the body, such as releasing from the food we eat. Proteins also function as transport proteins such as hemoglobin; an iron containing protein that transports oxygen to exercising muscles via the bloodstream.

Protein consists of building blocks called amino acids, which are linked together in different patterns to form specific proteins with different characteristics. There are twenty different amino acids of which eight are considered essential because they cannot be generated by the body but are necessary for survival. The body uses amino acids circulating in the blood stream, released from the breakdown of tissues, or consumed in the diet to make protein.

Protein in the diet

Unlike carbohydrate and fat, the body does not generally store protein, thus it is essential in the diet. Proteins vary in quality and are found in a variety of foods. A high quality protein, also known as a complete protein, contains all eight eproteinssential amino acids. A low quality or incomplete protein, on the other hand, is missing one or more of the essential amino acids. Complete proteins often come from animal sources such as beef, poultry, fish, eggs etc., whereas incomplete proteins usually include fruits, vegetables, grains, and nuts.

One concern with consuming complete proteins, is the saturated fat that tends to come with it. Beef and pork, although great sources of protein contain high amounts of saturated fats, and it is important to choose lean cuts of these meats and consume them in moderation. Chicken, turkey, ostrich, and fish are high quality proteins that contain less saturated fat. However, it is important to note that red meats are good sources of iron as opposed to white meats. Remember, iron is important for binding oxygen and optimizing physical performance. Therefore, red meats should not be eliminated from the diet, rather choosing lean cuts, consumption in moderation and alternating with white meats is recommended. Remember to vary your protein food choices.

For example, a 6 oz broiled Porterhouse steak contains 38 g of protein but also 44 grams of fat of which 16 are saturated. On the other hand, 6 oz of salmon contains 34 grams of protein and only 18 grams of fat of which 4 grams are saturated.

Being a vegetarian requires extra precaution and knowledge to consume a variety of protein sources to meet the body's needs. Incomplete proteins from a variety of plant foods can be consumed to create a source of complete protein in the diet. Incomplete proteins that are consumed in order to create a complete protein are referred to as ‘complementary proteins.'

There are health benefits associated with some of the incomplete proteins. For example, research suggests that people consuming nuts on a regular basis are less likely to have heart attacks or die from heart disease than people whom rarely eat them. Nuts contain healthy unsaturated fatty acids, which can help reduce the amount of the harmful cholesterol LDL and increase the good cholesterol HDL.

Soy protein is another source of protein that has shown to possess health benefits including reducing hot flashes, cholesterol levels, breast and prostate cancer, and osteoporosis. In addition, soy protein may reduce the risk of heart disease if at least 6.25 grams is consumed per day. Research is ongoing to study soy protein's long-term effects on human health.

Recommended protein intake

Protein is an important nutrient for athletes because exercise breaks down muscle proteins, which require repair and restoration. Although protein does provide calories, unlike carbohydrates, it is not a preferred energy source for exercise. If protein is used as an energy source, repair and restoration of muscle may be compromised.

Many athletes believe that consuming large amounts of protein will increase muscle mass. However, muscle mass and strength can only increase as a result of physical activity and NOT excess protein consumption. In fact, excess protein consumption could be converted and stored as fat in the body. Protein consumption does play an important role in the post exercise meal where it optimizes glycogen storage and promotes muscle repair and restoration.

estimate your protein needsThe recommended protein intake for the American population is 0.8 g/kg/day (~0.4 g/lb/day). However, athletes may have different needs depending on the duration and intensity of exercise, and frequency of training. Strength training athletes need about 1.4-1.8 g/kg/day (~0.6-0.8 g/lb/day) and endurance runners need about 1.2-1.4 g/kg/day (~0.5-0.6 g/lb/day) due to the stress on muscle fibers during exercise. In general, the recommended protein intake for athletes ranges from 1.0-1.8 g/kg/day (~0.4-0.8 g/lb/day) depending on the energy expenditure and demand of the exercise. Calculate your protein needs...

 

Does this mean that athletes need to increase their protein intake or take supplements? The typical American consumes 1.5 g/kg/day (~0.7 g/lb/day), thus an increase in protein intake or protein supplementation is not needed in most instances. In addition, athletes tend to consume more protein because they are consuming more calories. 

Example – a 185 pound football player engaging in a strenuous strength and condition program would estimate his protein needs as 1.6 gm/kg (0.73 gm/lb). His protein needs are 135 gms daily. Although this sounds like a lot, the menu below shows just how easy it is to meet the daily protein needs – even the strength training athlete.

 

 

Diet meeting 136 gms of protein
Breakfast
3 egg omelet (18 gms protein)
1.5 oz cheese (11 gms protein)
2 slices of toast (6 gms protein)
16 oz of skim milk (16 gms protein)
  eggstoastmilk
     
Lunch
Chicken breast sandwich (35 gms protein)
3 oz chicken breast, 6” bread, 1 oz cheese, Veggies
Water
  sub sandwichmilk
     
Dinner
2 cups of pasta (12 gms protein)
Meat sauce w/
3 oz ground beef & 1/2 c marinara sauce (23 gms protein)
16 oz of skim milk (16 gms protein)
  spaghettimilk
 

 

Health implications

Lack of protein consumption can lead to serious conditions such as decreased immunity, stunted growth, heart and respiratory failure, and death. Conversely, excess protein intake has been associated with calcium resorption from bone as a response to the disruption of acid/base balance. The key to protein consumption is as with other nutrition recommendations – moderation.

Protein content of foods
Food Serving Grams of protein
Egg 1 large 6
Ground beef 3 oz 21
Top round beef 3 oz 26
Chicken breast (w/o skin) 3 oz 29
Chicken nuggets 6 pieces 14
Turkey breast (roasted) 3 oz 13
Salmon 3 oz 23
Tuna 3 oz 25
Milk 1 cup 8
Yogurt 1 cup 10
Cheddar cheese 1 oz 7
Cottage cheese 1/2 cup 14
Tofu 1/2 cup 10
Lentils 1 cup 18
Baked beans 1 cup 14
Green beans (boiled) 1/2 cup 1
Kale (boiled) 1/2 cup 1
Kidney beans (canned) 1 cup 13
Corn (yellow, boiled) 1/2 cup 3
Brussels sprouts (boiled) 1/2 cup 2
Carrots (raw) 1 medium 1
Chickpeas (boiled) 1 cup 14
Broccoli (boiled) 1/2 cup 2
Avocado 1 medium 4
Banana 1 medium 1
Cantaloupe (raw) 1 cup 1.4
Orange (raw) 1 medium 1
Raisins 2/3 cup 3.4
Peaches (dried) 10 5
Figs (dried) 10 6
Apricots (dried) 10 1.3
Kiwi (raw) 1 medium 1
Almonds (dried) 1 oz 6
Cashews (dry roasted) 1 oz 4
Coconut (milk) 1 cup 5
Hazelnuts (filberts, dried) 1 oz 4
Macadamia nuts (dried) 1 oz 2
Peanuts (dry roasted) 1 oz 7
Peanut butter (creamy) 2 tablespoon 8
Pecans (dry roasted) 1 oz 2
Sesame seeds 1 tablespoon 2
Soybean nuts (roasted) 1/2 cup 34
Sunflower seeds (dry roasted) 1 oz 6
Walnuts (black, dried) 1 oz 7
Pasta 1 cup 5
Bread 2 slices 6

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