September 2009 - Vol 4 Issue 9

The Power of Protein
Why we need protein and how to get enough
by Michelle Gibeault Traub, R.D.

Protein has been very popular in the past decade. The high protein diet craze caught on quickly when people realized how filling protein foods were. However, when dieters overloaded on meats and cheese, health professionals warned that such high fat foods were too low in crucial nutrients like calcium, other minerals, and vitamins. Before long protein was getting a bad rap with concerns that the nutrient could cause bone loss or kidney damage. While these warnings have merit, the reality is still that many people are not getting the protein they need. In addition, protein does much more than keep us full. It is crucial for building muscle, giving flexibility to bones, and even in contributing to beauty. 

What does protein do?

Before its link to weight loss, protein got very little attention. This is a shame when you consider the structural role this nutrient plays in the body. You probably already know that our muscles are made of protein, but you might not realize that bones are high in protein too. In addition to calcium and other minerals, bones contain collagen, a protein that helps to provide flexibility. Collagen is also a key beauty nutrient as it contributes to healthy hair, nails, and skin. Protein is also necessary for blood and immune cell function and enzymatic reactions throughout the body. Since protein is not stored in the body, not getting enough every day can decrease muscle strength, cause hair loss, and increase the risk of infection.    
  
Estimating protein needs

During the low carb craze, although eating more protein was emphasized, only carbohydrate grams were “counted.” Therefore, few people really knew how much protein they were getting in their diets. This issue is not a problem for many Americans who easily meet protein needs set by the Institute of Medicine (IOM) at .8 grams for every kg (or 2.2 pounds) of body weight. However, reports indicate that for adolescents and older women protein intakes may be insufficient. Furthermore, the guidelines for protein intake set by the IOM are designed as the minimum amount needed for muscle maintenance, other guidelines such as the Acceptable Macronutrient Distribution Range (AMDR) offer a much broader view of protein needs with a range of 10 to 35 percent of daily calories considered ideal. (See Protein Needs for a chart of protein requirements by weight and calorie intake).  

The best protein sources

Protein is actually composed of smaller components called amino acids. Although our bodies can make some amino acids, additional “essential amino acids” are required from the diet in order to build tissue proteins. The traditional diet of an omnivore (someone who eats meat) is loaded with ample complete proteins which contain all the essential amino acids. Yet, it is important to remember that while meats and dairy products are great protein sources, they can also be very high in saturated fats which can contribute to heart disease. This problem is easily avoided by choosing only lean cuts of meat and low fat dairy products. Vegetarians, on the other hand are lucky enough to have protein options that are lower in saturated fat, but they must be mindful about eating a wide variety of protein sources to get all of the essential amino acids. The following are healthy protein choices for both diets:

High Protein Foods for Omnivores

• Lean meats (skinless poultry, pork, lean beef)
• Eggs and egg substitutes
• Fish
• Low fat dairy products (yogurt, cheese, etc.)

High Protein Foods for Vegetarians

• Beans
• Nuts & seeds
• Soy products
• Whole grains

Protein problems

Like most other nutrients, getting too much protein can be problematic. Consuming too much protein, particularly from animal products, can lead to an acid imbalance in the body which some researchers believe causes calcium to be taken from the bones. These researchers warn that high protein diets are bad for bone. Yet, not all experts agree with this belief since some studies have shown that high protein diets may help with calcium absorption. Likewise, given the protein content of bone, moderate protein diets likely benefit bones and the muscles that support them. But, as usual, the key is moderation. Eating excess protein impacts more than bone health. When protein is eaten as a replacement for carbohydrates side effects can include headaches, nausea, irritability, and kidney problems. Protein can be difficult for the kidneys to breakdown, so long term intakes of high protein may impact kidney function, and those with active kidney disease must be extra cautious with protein intake. Finally, eating too many high protein foods can take the place of fruits and vegetables which are necessary for the fiber, vitamins, and minerals they provide.

Overall, protein is a very powerful nutrient. As long as you meet your daily protein requirements your muscles and bones are able to stay strong, your immune system is able to fight off disease, and your hair, skin, and nails can stay healthy and beautiful.

Resources

• Harvard School of Public Health. Protein: Moving Closer to Center Stage, The Nutrition Source, retrieved 8/31/09 LINK



• Mary Jo Feeney, MS, RD, FADA. Protein’s Role In Promoting Optimal Health: Beyond Nitrogen Balance. Health Connections. Issue 6, Vol 3, Spring 2009.



• Karl Insogna, M.D., Carolyn M. Mazure, Ph.D., Jane Kerstetter, Ph.D. Understanding How Nutrition Affects Bone Health. Women’s Health Research at Yale. retrieved 8/31/09 LINK (PDF)

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