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What Are Amino Acids?

Nutrition | February 20, 2017 | Author: Naturopath

diet

What Are Amino Acids?

The proteins we eat help build our muscles, bones, skin, cartilage, and blood. They provide us with energy, and are needed for the structure and function of hormones, enzymes, antibodies, and tissues.

What exactly is protein?

Along with fat and carbohydrates, protein is a macronutrient, meaning the body requires it in large amounts for energy.

When we eat protein, the body breaks it down into small molecules that are attached to one another to form a long chain. These molecules, called amino acids, are the building blocks that make up protein.

There are 20 amino acids. Our bodies can make all but 9 of the 20 amino acids. As a result, they must come from the food we eat, and are therefore called essential amino acids. They include phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.

Animal sources of protein, including meat, poultry, fish, eggs and cheese, contain all of the essential amino acids, and as such are considered to be complete proteins. Plant foods, such as fruits, vegetables, legumes, grains, nuts and seeds, are referred to as incomplete proteins. Although they also contain protein, some may lack one or more essential amino acids. Unlike carbohydrate and fats, the body does not store protein. Thus, it is important that we consume adequate protein. Each amino acid has specific functions in the body, such as making certain hormones and neurotransmitters. Consume too little, and your body will start breaking down muscle in order to get the amino acids it needs.

How much protein?

In general, it is recommended that 10-35 percent of your daily energy intake comes from protein.

According to the National Health and Medical Research Council (NHMRC), the recommended amount you should eat every day is:                                                                

  • 64 grams per day for men (or approximately 0.8 g of protein for every kilogram of body weight per day)
  • 46 grams per day for women (or approximately 0.75 g of protein for every kilogram of body weight per day)

In Australia and most developed countries, most people consume adequate protein to prevent deficiency. However, you may need extra if you are:

  • Over the age of 70. Elderly persons are at risk of developing protein-energy malnutrition, a disorder caused by an intake of poor quality dietary protein or by inadequate dietary intake of protein, due to increased demands because of disease, decreased appetite, and lack of variety in their diet. 

Furthermore, body composition changes as people get older, manifested in decreased skeletal muscle. The American College of Sports Medicine suggests that in order to maintain muscle mass, you need to increase the protein in your diets as early as around 50 years of age.          

  • Active. If you do a lot of high-intensity workouts, the Australian Institute of Sport recommends increasing your protein intake in order to help with recovery and performance.
  • Vegetarian or vegan. A large study (EPIC-Oxford) compared the nutrient intakes of about 30,000 meat-eaters, 10,000 no meat except fish-eaters, 20,000 vegetarians, and about 2,500 vegans. Overall, meat-eaters were found to consume higher amount of protein than the other dietary groups, and the lowest protein intake was among the vegans. However, most dietary groups consumed over the minimum protein requirements.

The bottom line? The overall daily protein recommendation for vegetarians is the same as for every healthy person. Vegans may benefit from a slightly higher amount of protein. As plant-based proteins may not have all the essential amino acids our bodies need, both vegetarians and vegans need to eat a variety of plant sources each day to ensure intake of all essential amino acids.

  • Pregnant or breastfeeding. Extra protein is required for pregnancy and lactation, with increasing amounts recommended for each trimester.
  • Trying to lose weight. Protein is considered to be the most satiating macronutrient. Increased satiety helps to decrease energy (calories) intake, which is necessary for successful weight loss. Research suggests that high-protein diets are effective for both short and long-term weight loss.

The problem with High-Protein Diets

More is not necessarily better! The increased acid load in high-protein diets may put a strain on the kidneys. It is advisable that patients with pre-existing kidney disease should consume low-to-moderate protein diets. It has also been suggested that the high fat content of animal proteins (e.g. red meats, eggs and dairy products) may put consumers of high-protein diets at higher risk for heart disease.

Eating red meat, especially processed red meat, is linked to an increased risk of not only heart disease but also type 2 diabetes and cancer.

Choose your protein wisely

Protein quality matters more than protein quantity.

  • Avoid processed meat, such as ham, sausage, frankfurters, and deli meats.
  • Replace red and processed meat with nuts, beans, fish, poultry, or soy protein.

Plant foods that contain complete proteins

Although most plant-based foods are incomplete, meaning they do not contain the nine essential amino acids we need, there are a number of plant-based foods that do provide complete proteins. They include:

  • Quinoa
  • Amaranth
  • Buckwheat
  • Soy
  • Chia seeds
  • Flax seeds

Tips for taking amino acid supplements

Amino acids can be taken individually or in different combinations as supplements.

Getting them from your diet is best, but for certain conditions taking amino acid supplement can be beneficial.

  • Look for amino acids in the L- form, which are considered to be more compatible with human biochemistry.
  • When taking amino acids individually, take them on an empty stomach for better absorption.
  • When taking an amino acid complex, take 30 minutes away from meal, before or after.
  • Do not take individual amino acids for a long period of time.
  • Always follow the recommended dose.
     

References

Academy of Nutrition and Dietetics 2014, Protein in Vegetarian and Vegan Diets, Eat Right, retrieved February 14, 2017

American College of Sports Medicine 2015, Protein intake for optimal muscle maintenance, ACSM, retrieved February 14, 2017

Australian Government National Health and Medical Research Council 2014, Nutrient Reference Values for Australia and New Zealand, Protein, NHMRC, retrieved February 14, 2017

Australian Government Australian Sports Commission 2009, Protein, AIS, retrieved February 14, 2017

Balch, P.H 2006, Prescription for nutritional healing, Avery, London, England

Davey, G. K., Spencer, E. A., Appleby, P. N., et al. (2003). EPIC–Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK. Public Health Nutrition, 6(3), 259–69

Harvard School of Public health 2017, The Nutrition source: Protein. Harvard, retrieved February 14, 2017

Institute of medicine Food and Nutrition Board (2005), Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients), IOM. Washington, D.C.: National Academies Press.

Murray, M.M, Pizzorno, J., Pizzorno, L.,2005, The encyclopedia of healing foods, Atria Books, New York, USA

Pesta, D. H., & Samuel, V. T. (2014). A high-protein diet for reducing body fat: mechanisms and possible caveats. Nutrition & Metabolism, 11(1), 53.

Phillips, W. (2014). Nutrition issues in gastroenterology, series #133: Coding for malnutrition in the adult patient: what the physician needs to know., practical gastroenterology, September 2014

Scheinfeld, N.S. (2016), Protein-Energy Malnutrition: Background, Pathophysiology, Epidemiology. Medscape, retrieved February 14, 2017 < http://emedicine.medscape.com>

World Health Organization 2007, Protein and amino acid requirements in human nutrition Report of a joint FAO/WHO/UNU expert consultation, WHO, retrieved February 14, 2017

 

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