Ask the Nutritionist

Q: My husband was recently diagnosed with very advanced (stage IV) and very aggressive prostate cancer. He has evolved from a high protein diet (including a significant amount of red meat) to a modified vegan diet (he will eat fish). Is this a good idea? What do you recommend for someone who is 60 years old and very healthy in all other regards, except for his prostate cancer?

AKL, Salem, Massachusetts 

A: There are advantages and disadvantages to a vegan diet (excluding all animal products) for any person.

The advantages:

• Studies show that plant-based diets provide important antioxidants and phytonutrients that work together to reduce the risk of developing various types of cancer and help to support the immune system.
• These diets ultimately include more plant foods such as fruits, vegetables, whole grains, soy, nuts, and beans, all of which are very nutritious.
• Also, limiting your options forces you to be more conscious of your food choices, and may cause you to make better decisions.

Disadvantages:

• A vegan diet limits the amount of protein you get in your diet. Protein is an important part of any well-balanced diet, and it is particularly important for cancer patients because it is needed to repair damaged cells and help your body recover and maintain a healthy weight.
• This diet can also be quite restrictive on a person's vitamin D intake, as this nutrient is found primarily in fortified dairy and fatty fish, such as salmon, mackerel, and tuna. Vitamin D deficiency is common in northern parts of the United States, particularly in the winter months when our skin cannot make the vitamin from the sun.
• Vitamin B12, iron, and calcium levels should also be monitored, as these vitamins are found mostly in animal products.

What does this mean for someone fighting prostate cancer?

Bottom line: You do not have to be a total vegan to eat well, but we highly recommend a plant-based diet that revolves around whole grains, fruit, vegetables, beans, and nuts. Fish, poultry and low-fat dairy are also components of a healthy diet.

Start with 5-10 servings of fruits and vegetables every day, and combine that with lean protein (fish, poultry, legumes, beans, nuts, nut butters, and low-fat dairy), healthy fats, and whole grains, and you're on your way to building a strong immune system and a healthy body.

In regard to vitamin D, you can ask your doctor to check your husband's blood levels with the 25-OH vitamin D test. Be sure he is getting enough: typically, 1,000 International Units (IUs) per day and no more than 2,000IU.

A daily multivitamin that contains iron, B12, calcium, and vitamin D is recommended for anyone following a vegan diet.