#185 6 Protein Sources that May Shorten Your Life

6 Protein Sources that May Shorten Your Life

Not all protein sources are the same when it comes to longevity.  In this article, I review a recent Harvard University study which reported that 6 protein sources could shorten your life.

Jin’s Experience

On our last trip to China’s Longevity Village, I met Jin.  It was a hot summer night in Southwest China and the entire village had come together to prepare for a wedding.  As part of this wedding preparation, we had the honor of being the guests of the district mayor.

Shortly after arriving, a man in his 30’s called for me to sit next to him.  As he was in charge of making the tofu, and I was eager to learn how to make tofu, I sat down next to him.

“Are you American?” Jin said in Chinese.

“Yes,” I replied back in Chinese.  “Have you always lived here?” I asked.

“No.  I grew up in the village but then moved to Guangdong for work.  I recently retuned for health reasons,” he said.

Jin, like most younger men in this part of China, left their rural villages for the higher paying jobs in the big Chinese cities.  In Guangdong he had cash and could afford the things he never experienced as a child.

His favorite indulgence was Kentucky Fried Chicken or KFC.  He went from meat being a special treat on perhaps just one day of the week to lots of meat with every meal.

While he didn’t notice much at first, little by little his health declined.  Seven years after leaving the Village, he was fatigued and also started developing chest pains and shortness of breath.

His parents urged him to return to the village to recover.  After much pleading, he gave in and left his higher paying big city job.  Within just three months of returning home, his health was restored.

Do protein sources affect health?

The cardiologist side of me couldn’t help but to analyze his experience.  It goes without mention that life in rural China is vastly different than the high stress, big polluted cities of China.

In addition to the village versus city life, he had also traded a mostly vegetable based diet for a mostly meat based diet.  As I made tofu with him that night, I couldn’t help but wonder if the vegetable protein sources protected him in a way that the meat protein sources couldn’t.

The Harvard Protein Study

With the growing popularity of high protein, low carb diets, Harvard researchers wanted to know if how you got your protein mattered.  To find out, they studied 131,342 doctors and nurses for up to 32 years.

This Harvard study asked a simple question, what would happen if you just replaced one serving daily of meat or dairy with a plant-based protein.  In other words, would it matter if say you replaced one serving of say bacon with protein from a serving of vegetables, beans, lentils, nuts, or seeds.

6 Protein Sources that May Shorten Your Life

After carefully analyzing the data from these 131,000 doctors and nurses, Harvard researchers found that how you get your protein may determine your lifespan.  In particular, replacing one serving daily of the following 6 protein sources with plant-based protein sources could significantly lengthen your life.

1. Replacing 1 serving of processed red meat: 34% longer life

2. Replacing 1 serving of eggs: 19% longer life

3. Replacing 1 serving of unprocessed red meat: 12% longer life

4. Replacing 1 serving of dairy: 8% longer life

5. Replacing 1 serving of poultry: 6% longer life

6. Replacing 1 serving of fish: 6% longer life

It goes without saying that if you substitute processed foods for meat and dairy, your health will suffer.  To gain any possible health benefit, all substitutions need to be with unprocessed whole foods, like vegetables, beans, lentils, nuts, or seeds.

Protein Sources Don’t Matter for Some People

For some people in this study, protein source didn’t affect their longevity.  Interestingly, these Harvard researchers found that only people with risk factors for heart disease benefited from plant-based protein sources.

Thus, according to this study, if you don’t smoke, don’t drink much alcohol, exercise every day, and are at a perfect weight, then meat and dairy doesn’t seem to shorten your life.  Perhaps this is because an otherwise healthy lifestyle negates any possible risk from meat and dairy.  Regardless, this is a new finding that needs to be confirmed in future studies.

Can you believe this study?

As you know, nutrition science is not perfect.  And this study is no exception.

First of all, this study doesn’t prove that eating more plant-based protein sources is going to make you live longer.  It also doesn’t prove that if you don’t smoke or drink, exercise every day, and are at the perfect weight that you can eat all the processed red meat you want and not have your life cut short.

Rather, all this study tells us is that, of these 131,000 doctors and nurses, those who ate more plant-based protein sources were observed to live longer.  While researchers tried to control for other dietary and lifestyle factors, they may not have been able to control for everything.  For example, studies show that heavy meat eaters generally don’t exercise, tend to be overweight, and are more likely to smoke and drink.

In addition, I was very surprised to see that even replacing a serving of fish, with a plant-based protein, appeared to extend life.  This finding stands in sharp contrast to most studies which show that fish is good for your heart and may extend your life.

How can plant-based protein sources help you?

Food is information for your genes.  What you eat, including your protein sources, determines which genes are turned on and which genes are turned off.  Below are five possible reasons why eating more plant-based protein sources, like beans, lentils, nuts, seeds, and vegetables, may help you to live longer.

1. Plant-based proteins are associated with weight loss.

2. Plant-based protein sources don’t trigger the cancer hormone, IGF-1.

3. Plant-based proteins lower blood pressure.

4. Plant-based protein sources lower cholesterol.

5. Plant-based proteins protect against diabetes.

What are the best plant-based protein sources?

If you are not used to eating legumes, nuts, seeds, or vegetables, you may be surprised by exactly how much protein is packed in these foods.  Below are some examples.  To put these numbers in perspective, salmon has 17 grams of protein for every 100 calories.

1. Spinach: 13 grams of protein per 100 calories

2. Tofu: 11 grams of protein per 100 calories

3. Asparagus: 10 grams of protein per 100 calories

4. Lentils: 8 grams of protein per 100 calories

5. Broccoli and peas: 7 grams of protein per 100 calories

6. Pinto beans: 6 grams of protein per 100 calories

7. Peanuts: 5 grams of protein per 100 calories

Are plants a complete protein?

Many internet sites claim that plant proteins are poor protein sources because they are not complete proteins.  Despite these claims, medical studies debunked this myth decades ago.

A complete protein is a protein that contains an adequate amount of all nine essential amino acids.  In general, if you eat some meat and dairy, or you eat a variety of plant-based protein sources, then your body will naturally get all nine essential amino acids.

On a separate note, if you don’t eat much meat, please speak with your doctor about whether or not you should take a vitamin B12 supplement.

Take Home Message

The main take away from this recently published Harvard study, is that most people would likely enjoy better health by eating a little less meat and dairy, especially processed red meat, and a little more vegetables, legumes, nuts, and seeds.

While it wasn’t the main finding of this study, if you exercise every day, maintain a perfect weight, don’t smoke, and don’t drink much alcohol then meat and dairy doesn’t appear to cut your lifespan.  This new finding needs to be confirmed in future studies.

For the time being, if you are a heavy meat eater and need help cutting back, start thinking of meat as a special treat. In deference to environmental and health concerns, a lot of people have adopted “Meatless Mondays.”  With the Meatless Mondays movement, for one day a week people follow a plant-based diet with or without dairy.

Have you tried substituting more plant-based protein sources?  What has your experience been?

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  1. This article reminds me of the McDougall plan by John a McDougall and the China study by T Colin Campbell good advice thank you

  2. Hi Dr. Day,

    I Loved the Six Proteins article. With today’s mindset that the only source of protein is from animal products, it was a nice nudge to get people thinking about other more healthy plant based sources of protein. I also think it was good because aren’t we starting to see more evidence that because America’s major source of protein is meat that we are eating more protein than we actually need, which leading to health issues associated with excess protein?

    • Great point. While I didn’t cover the topic of excess protein in this article, there are some studies suggesting that there may be harm from the excessive amounts of protein in the Standard American Diet…will save these studies for a future article.

      Thanks for reading and commenting!