Five Popular Diets: Are they right for cancer survivors?

Suzanna Zick, N.D., MPH, reviewed five diets: the alkaline, Paleolithic, ketogenic, vegan/vegetarian and macrobiotic to learn which was best for cancer survivors.

Alkaline Diet

The philosophy is that cancer is caused by an acidic environment in the body, resulting from too many refined carbohydrates and animal fats, like red meat, pork and white flour.

If a person eats more fruits and vegetables and limits red meat, sugar and white flour/rice, more alkaline ions are available after digestion. The extra alkalinity decreases the acid load and helps reduce the strain on acid-detox systems.

"There is very limited data that the acid nature of your body causes cancer, but by increasing fruits, vegetables and whole grains, and by limiting red meat and simple carbohydrates, you’re essentially following the American Cancer Society and World Cancer Research Fund/American Institute for Cancer Research’s guidelines for cancer patients and survivors, and eating foods that decrease cancer mortality and recurrence," Zick says.

Paleolithic (Paleo) Diet

The Paleolithic diet attempts to replicate the dietary pattern of Stone Age humans -- the hunter-gatherers who ate fruits, vegetables, nuts, meat and eggs -- while excluding grains, legumes, dairy products and processed foods.

But strict adherence eliminates food groups, like beans and whole grains, proven to be beneficial for preventing cancer, decreasing cancer mortality and improving general health.

Zick says this diet tends to have people eat too much red meat, which could increase one’s risk of colorectal cancer, although it does emphasize whole foods, fruits and vegetables.

Ketogenic (Keto) Diet

The keto diet emphasizes a high-fat, low-carbohydrate meal plan. This approach shifts the energy source of cancer cells away from glucose to ketones.

Evidence suggests that some cancer cells appear less able to metabolize ketones compared with healthy cells, while other experiments show tumor cells use ketones for energy.

The diet is difficult to follow long term and patients often fail to reach the proper level of ketones. It also promotes nutrient deficiency and includes processed foods.

Vegan / Vegetarian Diet

The heart of the vegan diet is abstinence from eating animal products, such as meat, fish, eggs, dairy and honey. It encourages cancer-fighting foods, including berries, greens, whole grains, nuts and seeds.

However, there are many highly processed and sugar-filled vegan and vegetarian foods. "The problem is you can eat poorly while being a vegan or a vegetarian," Zick says. So attention needs to be put on whole plant foods and less-processed foods to optimize the benefits of this diet.

Macrobiotic Diet

Imbalance in the body can cause illness such as cancer, according to the Eastern philosophy behind a macrobiotic diet.

The diet is predominantly vegetarian and emphasizes unprocessed, organic, whole foods. Cereal grains, like rice and millet, make up 40-60% of the diet, while vegetables and legumes split the rest. It remains a good choice because it meets most of the dietary ACS and AICR guidelines.