Do High Protein Diets Cause Cancer?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

How Much Protein Should We Eat?

Author: Dr. Stephen Chaney

Animal Protein FoodsThe recent headlines suggesting that high protein diets may cause cancer, diabetes and premature death in middle aged Americans are downright scary. You are probably asking yourself:

  • “Is this new information?”
  • “Does this apply to me?”
  • “Should I radically change what I eat?”

In this issue of “Health Tips From the Professor” I will address each of these questions.

Do High Protein Diets Cause Cancer?

The study in question (Levine et al., Cell Metabolism, 19: 407-417, 2014) suggested that high protein diets were associated with increased risk of cancer, diabetes and premature death in Americans in the 50-65 age range. I will touch on all three of these observations, but it is the increased risk of cancer that generated the most headlines – and the most concern (The consequences of diabetes take years to manifest, and death seem to be a more distant concern for most people. Cancer is immediate and personal).

The study looked at 6,381 adults aged 50 and older (average age 65) from the NHANES III data base. (NHANES is a comprehensive database collected by the Centers for Disease Control and Prevention that consists of surveys and physical examinations and is designed to be representative of the health and nutritional status of the US population.)

The data collected consisted of a single diet questionnaire conducted when the subjects were enrolled in the study. Based on the diet questionnaire the authors of the study divided the group into those with low protein intake (<10% of calories), those with moderate protein intake (10-19% of calories) and those with high protein intake (>20% of calories). Overall death and mortality from various diseases over the next 18 years was obtained by linking the NHANES data with the National Death Index.

Based on preliminary data suggesting that the age of the population might influence the results (I won’t go into details here) the authors of the study decided to subdivide the dataset into people aged 50-65 and people over 65. When they did that, they came to the following conclusions:

1)     In the 50-65 age group diets high in animal protein were associated with a:

  • 45% increase in overall mortality
  • 4-fold increase in cancer death risk
  • 4-fold increase in diabetes death risk.

Diets with moderate protein intake were associated with intermediate increases in risk. Surprisingly, there was no increase in cardiovascular disease risk.

Protein Shakes2)     When they looked at people in the 50-65 age group consuming diets high in vegetable protein:

  • the increased overall mortality and increased in cancer mortality disappeared
  • the increased diabetes mortality was still seen.

3)     In the 65+ age group high protein diets were associated with a:

  • 28% decrease in overall mortality
  • 60% decrease in cancer mortality.

The increased risk of diabetes related deaths was still observed. The authors did not distinguish between animal and vegetable protein in the over 65 age group.

All of that may seem to be a bit too complicated. At the risk of gross oversimplification I would summarize their message as follows:

  • Diets high in animal protein may be bad for you if you are in the 50-65 age range, but might actually be good for you if you are over 65.
  • Diets high in vegetable protein appear to be good for anyone over age 50 (The study didn’t look at younger age groups).

Is This New Information?

Let’s start by assuming that the conclusions of the authors are correct (more about that below).

When you boil their message down to its simplest components, the information isn’t particularly novel.

  • The idea that vegetable proteins may be better for you than animal proteins has been around for decades. There are a number of studies suggesting that diets high in animal protein increase the risk of cancer, heart disease, diabetes and overall death – although it is still not clear whether it is the animal protein itself or some other characteristic of populations consuming mostly animal protein that is the culprit.
  • Evidence has been accumulating over the past decade or so that protein needs increase as we age, so it is not surprising that this study found high protein diets to be beneficial for those of us over age 65.

What Do Other Experts Say?

ScientistSince this study has been released it has been roundly criticized by other experts in the field. Let me sum up their four main criticisms and add one of my own.

1)     The protein intake data were based on a single dietary survey taken at the beginning of an 18 year study. The authors stated that a single dietary survey has been shown to be a pretty accurate indicator of what an individual is eating at the time of the survey. However, it is problematic to assume that everyone’s diet remained the same over an 18 year period.

2)     The choice of less than 10% of calories from protein is also problematic. According to the Institute of Medicine standards anything below 10% is defined as inadequate protein intake, which can have long term health consequences of its own.

More importantly, only 7% of the population being studied (437 individuals) fell into this group. This is the baseline group (or put another way, the denominator for all of the comparisons). The conclusions of this study were based on comparing the other two groups to this baseline, and there were too few individuals in this group to be confident that the baseline is accurate.

This does not necessarily invalidate the study, but it does decrease confidence in the size of the reported effect – so forget the reported numbers like 45% increase in mortality and 4-fold increase in cancer deaths. They probably aren’t accurate.

3)     The number of people in this study who died from diabetes was exceedingly small (68 total) and most of them already had diabetes when the study began. The experts concluded that the numbers were simply too low to draw any conclusions about protein intake and diabetes related deaths, and I agree with them.

4)     While the study controlled for fat intake and carbohydrate intake, it did not control for weight. That is a huge omission. Overweight is associated with increased risk of cancer, diabetes and death, and vegetarians tend to weigh less than non-vegetarians.

5)     I would add that there are many other differences between vegetarians and non- vegetarians that could account for most of the differences reported between diets high in animal and vegetable protein. For example:

  • Vegetarians tend to be more health conscious and thus they tend to exercise more, consume more fiber, consume more fruits and vegetables, consume less fried food, and consume less processed and convenience foods – all of which are associated with decreased risk of cancer, diabetes and death.

The Bottom Line:

This is not a particularly strong study. Nor is it particularly novel. In fact, when you strip away the scary headlines and focus on what the data really show, the conclusions aren’t that different from what nutrition experts have been saying for years.

1)     This study suggests that if you are in the 50-65 age range, diets high in animal protein may not be good for you (this study focused on increased risk of cancer death and overall mortality. Other studies have suggested that diets high in animal protein may increase the risk of cardiovascular death).

This is not a new idea. These data are consistent with a number of other studies. However, none of these studies adequately assess whether the increased risk is from the animal protein alone or from other characteristics of populations that consume a lot of animal protein.

2)     This study also suggests that diets high in vegetable protein do not increase either cancer risk or all cause mortality. That’s also not new information. We’ve known for years that people who consume primarily vegetable protein appear to be healthier. Once again, it is not clear whether it is the vegetable protein itself that is beneficial or whether the benefit is due to other characteristics of populations who consume a lot of vegetable protein.

3)     Does that mean that you need to become a vegetarian? It probably reflects my personal bias, but I am reminded of a Woody Allen Quote: “Vegetarians don’t live longer. It just seems that way”. I am also encouraged by studies suggesting that most of the health benefits of vegetarianism can be achieved by diets that consist of around 50% vegetable protein.

I would never discourage anyone from becoming a vegetarian, but if you aren’t ready for that, I would highly recommend that you aim for at least 50% vegetable protein in your diet.

4)     Finally, this study suggests that a high protein diet is beneficial for people over 65. This is also not a completely novel idea. It is consistent with a lot of recent research.

My advice to those of you who, like me, are over 65 is to pay attention to high protein foods and make sure that they are an important part of your diet. I’m not suggesting that you go for the double bacon cheeseburger just because you are over 65. I would still aim for a significant percentage of vegetable protein as a part of a healthy diet at any age.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Tags: , , , , , ,

Trackback from your site.

Comments (2)

  • Robert D. Munson, Ph.D., St. Paul, MN

    |

    Have you seen the documentary video, Forks Over Knives? In one part of it, as I recall, in a cancer study,dietary protein from milk was consumed at 5% and at 20%. Under the 5% cancer tumors shrunk, but grew under the 20% level. Have you reviewed Dr. Joel Fuhrman’s video, 3 Steps to Incredible Health , or Immunity Solutions? He leans heavily on various vegetables, especially salads (as a main meal).

    I believe that in many cases we do not pay enough attention to the cation make up of our diet. In general, potassium or magnesium are often neglected. Various elements activate enzymes, and influence cellular structures, such as the endoplasmic rheticulum, where cellular proteins are programmed. K/Na relationships are important in that regard. Cations also influence cytoplasmic streaming which influence rates of reaction within cells. Most of our diets in the U.S. are way to high in Na, especially in process and fast food operations.

    I really appreciate your analyses of various subjects. Thank you so much for all you do. I appreciate your discussion of on Cancer last evening.

    Reply

    • Dr. Steve Chaney

      |

      Dear Dr. Munson,
      I have seen “forks Over Knives”. There is a lot of good information in there. I think we could all benefit from a diet that included more fresh fruits and vegetables. I also believe in eating all things in moderation. For example, in the study you referred to 20% of protein from milk would be a lot of milk. It would be an unbalanced diet.

      You are also right on about mineral imbalances, We get far too much sodium in our diets and far too little potassium, magnesium and essential trace minerals.

      Dr. Chaney

      Reply

Leave a comment

Recent Videos From Dr. Steve Chaney

READ THE ARTICLE
READ THE ARTICLE

Latest Article

One of the Little known Causes of Headaches

Posted August 15, 2017 by Dr. Steve Chaney

Your Sleeping Position May Be Causing Your Headaches!

Author: Julie Donnelly, LMT – The Pain Relief Expert

Editor: Dr. Steve Chaney

 

Can sleeping position be one of the causes of headaches?  

A Sleeping position that has your head tilted puts pressure on your spinal cord and will cause headaches. I’ve seen it happen hundreds of times, and the reasoning is so logical it’s easy to understand.

causes of headachesYour spinal cord runs from your brain, through each of your vertebrae, down your arms and legs. Nerves pass out of the vertebrae and go to every cell in your body, including each of your organs. When you are sleeping it is important to keep your head, neck, and spine in a horizontal plane so you aren’t straining the muscles that insert into your vertebrae.

The graphic above is a close-up of your skull and the cervical (neck) vertebrae. Your nerves are shown in yellow, and your artery is shown in red.  Consider what happens if you hold your head to one side for hours. You can notice that the nerves and artery will likely be press upon. Also, since your spinal cord comes down the inside of the vertebrae, it will also be impinged.

In 2004 the Archives of Internal Medicine published an article stating that 1 out of 13 people have morning headaches. It’s interesting to note that the article never mentions the spinal cord being impinged by the vertebrae. That’s a major oversight!

Muscles merge into tendons, and the tendons insert into the bone.  As you stayed in the tilted position for hours, the muscles actually shortened to the new length.  Then you try to turn over, but the short muscles are holding your cervical vertebrae tightly, and they can’t lengthen.

The weight of your head pulls on the vertebrae, putting even more pressure on your spinal cord and nerves.  Plus, the tight muscles are pulling on the bones, causing pain on the bone.

Your Pillow is Involved in Your Sleeping Position and the Causes of  Headaches

sleep left side

The analogy I always use is; just as pulling your hair hurts your scalp, the muscle pulling on the tendons hurts the bone where it inserts.  In this case it is your neck muscles putting a strain on your cervical bones.  For example, if you sleep on your left side and your pillow is too thick, your head will be tilted up toward the ceiling. This position tightens the muscles on the right side of your neck.

sleeping in car and desk

Dozing off while sitting in a car waiting for someone to arrive, or while working for hours at your desk can also horizontal line sleepcause headaches. The pictures above show a strain on the neck when you fall asleep without any support on your neck. Both of these people will wake up with a headache, and with stiffness in their neck.

The best sleeping position to prevent headaches is to have your pillow adjusted so your head, neck, and spine are in a horizontal line. Play with your pillows, putting two thin pillows into one case if necessary. If your pillow is too thick try to open up a corner and pull out some of the stuffing.

 

sleeping on stomachSleeping on Your Back & Stomach

If you sleep on your back and have your head on the mattress, your spine is straight. All you need is a little neck pillow for support, and a pillow under your knees.

Stomach sleeping is the worst sleeping position for not only headaches, but so many other aches and pains. It’s a tough habit to break, but it can be done. This sleeping position deserves its own blog, which I will do in the future.

 

Treating the Muscles That Cause Headaches

sleeping position causes of headachesAll of the muscles that originate or insert into your cervical vertebrae, and many that insert into your shoulder and upper back, need to be treated.  The treatments are all taught in Treat Yourself to Pain Free Living, in the neck and shoulder chapters.  Here is one treatment that will help you get relief.

Take either a tennis ball or the Perfect Ball (which really is Perfect because it has a solid center and soft outside) and press into your shoulder as shown.  You are treating a muscle called Levator Scapulae which pulls your cervical vertebrae out of alignment when it is tight.

Hold the press for about 30 seconds, release, and then press again.

Your pillow is a key to neck pain and headaches caused by your sleeping position.  It’s worth the time and energy to investigate how you sleep and correct your pillow.  I believe this blog will help you find the solution and will insure you have restful sleep each night.

Wishing you well,

Julie Donnelly

 

About The Author

julie donnelly

Julie Donnelly is a Deep Muscle Massage Therapist with 20 years of experience specializing in the treatment of chronic joint pain and sports injuries. She has worked extensively with elite athletes and patients who have been unsuccessful at finding relief through the more conventional therapies.

She has been widely published, both on – and off – line, in magazines, newsletters, and newspapers around the country. She is also often chosen to speak at national conventions, medical schools, and health facilities nationwide.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

UA-43257393-1