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From:	Jeff Novick, MS, RD, LD, LN (novick.vegsource.com)
Subject:	Re: Protein FAQ im sure
Date:	December 26, 2008 at 6:18 pm PST

In Reply to: Protein FAQ im sure posted by Nick on December 26, 2008 at 3:04 pm:

Hi Nick

>>I'm having a lot of success eating

Define success. :)

>>mostly fruit and greens with some grains at dinner but when i plug my food into
nutridiary.com or some such site, I'm not even close to their recommended
levels.

I would not regard this as "success" especially without understanding the requirements for each nutrient, as while some are "bumped up" others are fairly accurate.

In the CR-ON studies (which is the only known way to extend lifespan in every single animal tested to date in over 75 years of studies, which BTW, is what I may call "success"), the goal is to reduce caloric intake while meeting all the RDA's/DRI's as for all the criticism about some of these numbers, they are still the best we have.

>>What do studies tell us about the USDA recommendation of .36 grams of protein
per body weight?

I am not sure exactly what you are asking and I am assuming you mean the RDA of .8 grams/kg body weight which equates to .36 grams of protein per pound body weight.

Some comments..

All nutrient recommendation are given in relation to the needs that will cover over 98% of the population over time and therefore include built in safety margins for most people. None of them ever represent the actual daily needs of any one person on any one day.

The only way to know the actual protein needs of any one person on any given day is to do a nitrogen balance study of that person on that day. But, realize that whatever your needs where today, they may be different tomorrow.

In regard to national recommendations (you may be interested in reading some of these documents)...

According to the National Academy of Sciences, Institute of Medicine,

http://books.nap.edu/openbook.php?record_id=10490&page=589

"The Recommended Dietary Allowance (RDA) for both men and women is 0.80 g of good quality protein/kg body weight/d and is based on careful analysis of available nitrogen balance studies."

For a 150 lb person, this would equate to about 55 grams

As a percentage of energy, from

From the Dietary Reference Intakes (DRIs): Acceptable Macronutrient Distribution Ranges Food and Nutrition Board, Institute of Medicine, National Academies

Protein 10–35% of calories.

On an 1800 calorie diet, 10% would equate to 45 grams

In grams, from

Dietary Reference Intakes (DRIs): Recommended Intakes for Individuals, Macronutrients Food and Nutrition Board, Institute of Medicine, National Academies

Adult men 56 g/day
Adult women, 46 g/day

From,

Protein requirements of adults, including older people, and women during pregnancy and lactation.(PROTEIN AND AMINO ACID REQUIREMENTS IN HUMAN NUTRITION) COPYRIGHT 2006 World Health Organization

Furthermore, recent detailed balance and body composition studies have shown that with a suitable program of resistance exercise sarcopenia (muscle loss) can be reversed and muscle strength increased on a protein intake of 0.8 g/kg per day (68 ). This intake is similar to the 1985 safe allowance and lower than usual intakes in this population.

(68 ) Campbell WW et al. Dietary protein adequacy and lower body versus whole body resistive training in older humans. Journal of Physiology, 2002, 542:631-642.

Now realize the .8 gram/kg is based on healthy weight, and includes a fairly liberal safety margin. Nitrogen balance studies have shown adults can maintain nitrogen balance on as little as .5 grams/kg though no one needs to shoot for the minimum. Patients who must limit their protein intake due to kidney issues are usually put on a diet that limits protein intake to around .5-.6 grams/kg and have been shown to actually build strength and muscle at that level.

Also, there is some evidence that in regard to longevity, that as we age, a lower (but adequate) protein intake may be better as it tends to keep levels of IGF-1 down which may be better to help reduce cancer risk and growth rates.

As long as you consume adequate calories to maintain a healthy weight from a variety of whole plant foods, (and not from junk foods and/or just fruit) you will more than likely get in all the protein you need. If you are not, then you may need to modify your intake.

In Health
Jeff

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