advertisement



Q & A Library


Print this page | Sign up for free e-bulletins
 | Bookmark This Page

Q
Too Much Meat in Middle Age?

Is it true that eating a high-protein diet when you're middle-aged doubles your risk of death, especially from cancer? I read that after age 65 moderate protein intake is good for you, but I don't understand why.

A
Answer (Published 8/11/2014)

You're likely referring to results of a analysis from the University of Southern California, Davis, suggesting that eating a lot of protein between the ages of 50 and 65 almost doubles your risk of dying, and quadruples the chances than you'll die of cancer compared to those in the investigation whose diets were low in protein. The researchers equated the risk of death from a high-protein diet to the risk of smoking, which certainly generated some scare headlines.

Related Weil Products
Dr. Weil on Healthy Aging - Your Online Guide to the Anti-Inflammatory Diet! - Everything you need to get started eating a healthful, satisfying diet is here - including eating and shopping guides, over 300 recipes, and an exclusive version of Dr. Weil's Anti-Inflammatory Food Pyramid! Start your 14-day free trial now - and start eating anti-inflammatory today!

The research team reviewed 18 years' worth of data on nearly 6,400 people aged 50 and older participating in the National Health and Nutrition Examination Survey that followed a representative group of adults over the age of 18. It concluded that the protein responsible for the risk of early death seen in this report was from animal sources – meat, milk and cheese – rather than vegetable protein. The researchers also found that the rates of cancer and death seen in the review were not affected by consumption of carbohydrates or fat.

They defined a "high-protein" diet as one that derives at least 20 percent of calories from protein, whether that protein comes from animals or plants, while moderate protein consumption is 10 to 19 percent of daily calories and a low-protein diet as one in which protein adds up to less than 10 percent of daily calories.

The review also showed that even a moderate daily intake of protein was associated with three times the risk of dying of cancer than that faced by participants whose protein consumption was low.

Surprisingly, the analysis also showed that after age 65, high protein consumption became far less of a threat and was, in fact, associated with reduced susceptibility to disease. The researchers attributed this finding to a dramatic age-related drop in IGF-I, a hormone influenced by protein intake that helps the body grow. IGF-I also has been linked to cancer susceptibility. The researchers suggested that high protein consumption after age 65 helps protect against potential frailty and muscle loss.

Not surprisingly, the report's findings have generated a fair amount of controversy. This was an observational investigation that associated high protein intake with more cancer and more deaths, but doesn't demonstrate scientifically that protein is the cause.

Critics have also faulted the report's conclusion that what is bad for 50 to 65 year olds is good for people over 65. British obesity researcher and author Zoe Harcombe criticized the researchers for failure to release raw data or provide a plausible explanation for why animal protein would be harmful to 50 to 65 year olds and "magically" helpful for those over 65. They suggested an explanation - the IGF-I connection - but haven't proved it. On her website, Harcombe also succinctly explains why observation isn't causation: "Just because we observe singing in the bath, it does not mean that being in the bath causes singing any more than singing causes being in the bath."

Andrew Weil, M.D.

Sources:
Valter D. Longo, Eileen M. Crimmins et al, "Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population". Cell Metabolism, 2014; 19 (3): 407-417 DOI: 10.1016/j.cmet.2014.02.006

Creative Commons License Some Rights Reserved Creative Commons Copyright Notice
A portion of the original material created by Weil Lifestyle, LLC on DrWeil.com (specifically, all question and answer-type articles in the Dr. Weil Q&A Library) is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

The Weil Vitamin Advisor
Get your FREE personalized vitamin recommendation & supplement plan today!

Dr. Weil on Healthy Aging
Your Online Guide to the Anti-Inflammatory Diet. Start eating for your health - begin your free trial now.

Dr. Weil's Spontaneous Happiness
Achieve emotional well-being
in just eight weeks!
Start your 10-day free trial now!

Vitamin Library
Supplement your knowledge with Dr. Weil's essential vitamin facts. Learn why they are necessary and more.

Dr. Weil's Optimum Health Plan
Your 8-week plan to wellness.
Begin your journey today!
 

Dr. Weil's Head-to-Toe
Wellness Guide

Your guide to natural health.
Use the Wellness Guide today!

Dr. Weil's Anti-Inflammatory Diet Food Pyramid
Our interactive tool can help improve overall health through diet.

Condition Care Guide
Learn about health conditions from acne to vertigo, and Dr. Weil's view of the best treatment options for each.

Healthy Recipes
Discover a treasure trove of healthy, healing foods and creative, delicious ways to prepare them.

Q&A Library
Over 2,000 questions from you
and their corresponding answers
from Dr. Weil.

 
Copyright © 2014 Weil Lifestyle, LLC
Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

Ad Choice
Advertising Notice

This Site and third parties who place advertisements on this Site may collect and use information about your visits to this Site and other websites in order to provide advertisements about goods and services of interest to you. If you would like to obtain more information about these advertising practices and to make choices about online behavioral advertising, please click here