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Lecture 6C- 15 FEB. 2015

PROTEINS

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DIETARY INTAKE RECOMMENDATIONS DRI -0.8 grams of protein per kg body weight/day healthy adults (19 and up) -10-35 percent of daily calories from protein -compare to 45-65 % from carbohydrate -compare to 20-35 % from fat

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PROTEIN ENERGY MALNUTRITION (PEM)

p.196-199

Kwashiorkor Ghanian word

Marasmus means to waste away

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PEM CONTINUED KWASHIORKOR 

PURE PROTEIN DEFICIENCY

-world wide –affects all ages-swollen liver and hence belly-LOW protein-HIGH fibre diet

-adequate energy intake-growth/immune issues-nutrient absorption

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MARASMUS ENERGY DEFICIENCY 

All nutrients including protein low in diet

Wasting-use of fat stores 

Growth issues-brain growth in first year potential for reduced intelligence and learning disabilities

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PROTEINS IN HEALTH-continued CANCER animal studies- initially believed to be soy protein that inhibited breast cancer but this turned out to be false

- actually isoflavones doing the job 

- one isoflavone binds to estrogen receptor reducing impact of estrogen

-estrogen (hormone replacement) has been linked to breast cancer

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PROTEINS IN HEALTH-continued HEART DISEASE

-increased dietary protein and reduced dietary fat

-generally decreases blood cholesterol levels-however animal protein tends to raise blood

cholesterol while plant protein tends to decrease blood cholesterol

 

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PROTEINS IN HEALTH-continued DIABETES 10-15 % caloric intake as protein- appropriate diabetics tend to consume more protein than non-diabetics - this can lead to kidney disease soy protein and other plant proteins improve kidney function in diabetic kidney disease compared to animal proteins

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PROTEINS IN HEALTH-continuedOSTEOPOROSISPathology-loss of bone mass 

In west, very high protein intake beyond recommended levels -this results in increased urinary calcium output 

Over a wide range of protein intakes for every 1 g increase in dietary protein get 1 mg increase in urinary calcium output 

So get higher levels of osteoporosis even with good calcium intakes

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PROTEINS IN HEALTH-continuedBLOOD PRESSURE  

Intervention studies show no relation with dietary amount or type

But individual amino acids like tryptophan or tyrosine decrease blood pressure in animals due to increases in blood pressure dropping neurotransmitters 

Arginine-may drop blood pressure due to blood vessel relaxation Also issue of reducing fat intake

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PROTEINS IN HEALTH-continuedKIDNEY FAILURE

Pathology- urea High protein diet suggested by some to increase progression of kidney disease to endpoint- controversial Higher protein intake associated with increasedkidney blood flow and filtration function-promotes renal failure

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PROTEINS IN HEALTH-continued IMMUNE RESPONSE Protein malnutrition 

-selective effects on immune cells- resulting in decreased immune function   -decreased immune maturation

 

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PROTEINS IN HEALTH-continued IMMUNE RESPONSE continued

Amino acids 

-arginine important for immune response 

-glutamine used for energy and DNA synthesis in immune response cells

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Athletes and protein supplements

Just eat more to meet increase energy needs and will get more protein in diet to meet increased demands on protein metabolism 

Whey protein and other amino acid/protein supplements are a waste of time and money for athletes and anybody else- supplements are expensive

-cheaper to get protein in a good diet.

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WHAT IS NEW IN PROTEIN NUTRITION RESEARCH?Gougeon R. Insulin resistance of protein metabolism in type 2 diabetes and impact on dietary needs: a review.

Canadian Journal of Diabetes 2013 Apr;37(2):115-20.

“the challenge remains to define the optimal protein intake and exercise regimen to protect from losses of muscle mass and strength while maintaining adequate glucose control in type 2 diabetes.”