Last week I had the opportunity to attend a seminar presented by Dr. T. Colin Campbell. For over 50 years he has been at the forefront of nutrition research. He holds the position of Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University. He’s written lots and lots of articles about nutrition as well as several expert food – and health – policy reports. He talked to us about some of his early research and where it has led him through the years.
Early in his career, he conducted research on how to end childhood malnutrition by figuring out how to get more high-quality protein into the children’s diets. The U.S. State Department’s Agency for International Development funded that study for the children of the Philippines. Dr. Campbell and his team chose peanuts as their protein source since peanuts are rich in protein and can grow under lots of different conditions.
At the same time, he was asked to study a cancer-causing chemical, which was produced by a fungus. There was quite a bit of evidence that this fungus caused liver cancer in lab rats (which means it probably also caused liver cancer in humans.) His job was to learn all he could about how the fungus grew so they could prevent it from growing on various food sources. One of the main foods this fungus contaminates is peanuts!
What he found as he got deep into this study turned his world upside down! The children of the Philippines who ate the highest-protein diets were the ones most likely to get liver cancer – even though these children with high-protein diets were wealthier and had better access to all the things we usually associate with childhood health, like medical care and clean water.
So they took this information to the lab and studied how protein affected the rats. They exposed all the rats with the cancer causing fungus. Then they fed some rats a 20% protein diet and the others a 5% protein diet. All the rats on the 20% protein diet started developing cancer while none of the rats on the 5% diet developed any sign of cancer.
So they changed the diet in the rats to just the opposite. The 20% protein was changed to 5% and the cancer started going away. The second group of rats on the 5% protein was changed to 20% and they started developing cancer. Then they switched them back to 5% protein and the cancer started going away! When they changed the 5% group to 20%, yep, you guessed it, the cancer started growing again.
The National Institutes of Health was so interested in this that they funded further studies for 27 years to verify this result!
Dr. Campbell and his team also tested this with animal protein and plant-based protein. They found that animal protein caused the cancer growth while soy and wheat protein did not increase the cancer development, even up to 20% of the calories! So the nutrients of animal based foods function differently from the nutrients of plant based foods.
What is the Recommended Daily Allowance (RDA) for protein? 10% of the calories eaten should be protein. This estimate, first made official in 1943, has since been officially reviewed 14 times by an expert panel of scientists, which has fixed this as a well-established percentage, according to Dr. Campbell.
If you are eating your protein from animal sources, it’s very important that you count your calories so you are not exceeding the 10% protein. However, if you are eating plant-based protein, you do not need to count your calories. Dr. Campbell states it’s very difficult to get more than 20% protein if you are eating a whole plant based diet.
This is just the first few minutes of my notes taken during Dr. Campbell’s first talk! There’s so much more that I’ll share in future columns. For now, consider what you are eating.