Is a vegan diet recommended for oncology patients?

October is Vegetarian Awareness Month and Meagan Atcheson explains the recommendations for oncology patients if they adopt a vegan diet, like nutritional requirements and getting enough protein.

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A healthy, well-planned vegan diet should always include variety. Focus particularly on the following: 

1. Plant-based proteins 
   • Tofu, tempeh, soya and legumes (beans, lentils, peas).
   • Nuts and nut butters: These are    sources of iron, fibre, magnesium, zinc and selenium. Particularly walnuts.
   • Seeds: hemp, chia and flaxseeds
2. Calcium-fortified plant milks and yoghurts – Look for ones that are fortified with calcium, B12 and vitamin D. Choose soya and almond milk which have higher protein content than rice, coconut and oat milk. 
3. Nutritional yeast – This has a cheesy flavour and can escalate the protein content of a meal. 
4. Whole grains, high-fibre cereals, complex carbs. For example, quinoa, chickpea pasta, wild rice, oats and starchy veg.
5. Fermented foods such as tempeh, miso, sauerkraut, kombucha. These contain probiotics and vitamin K2.
6. A variety of fruits and vegetables daily, especially the dark green leafy veg. 
7. Seaweed or a bit of iodised salt will help vegans reach the recommended daily intake of iodine.
8. Vegan protein powder 
9. Algal oil supplement 

Nutritional deficiencies

Following a vegan diet may increase the risk of nutritional deficiencies; vitamin B12, vitamin D, omega-3s, iodine, iron, calcium and zinc in particular. This can be particularly concerning when you have cancer because some of the treatments can put the body under a lot of stress and result in weight loss and loss of muscle mass. Compromising your nutrition by restricting your diet can heighten this effect and interfere with tolerance of treatment and hinder recovery.

It’s imperative that if you choose to go vegan that you don’t rely primarily on heavily processed convenience vegan food. Some vegans find it challenging to eat enough of these nutrient-rich and fortified foods to meet their daily requirements. Other supplements that may be beneficial include vitamin B12 and vitamin D3. 

Iron should only be supplemented if a deficiency is found. A vegan can enhance iron absorption from food by using iron-cast pots and pans for cooking, avoiding tea or coffee with meals, soaking grains and legumes before cooking and combining iron-rich foods with a source of vitamin C (lemon, citrus fruits, bell peppers).

Added cost

The added cost of supplements and plant-based alternatives should also be taken into account. For example, to get a similar amount of calcium as that in one glass of cow’s milk, you would need to consume: 200ml non-dairy milk or 60g of tofu or three medium oranges or four heads of raw broccoli. You would need to choose 2-3 servings of any of these a day just to meet calcium goals. 

Is it recommended?

While a nutrient-dense vegan diet has health benefits, it should definitely not be used to ‘kill’ cancer cells. Animal products are often feared by people facing cancer treatments due to the nutrition misinformation out there. For example, currently there is no evidence of any 

clear link between dairy and cancer. In fact, some studies show increased rates of cancer in those with a lower intake of dairy foods. Evidence does indicate that eating red meat (beef, pork, lamb) is a probable cause of colorectal cancer, but that processed red meat is a convincing cause of colorectal cancer.

Over time, many vegans switch to following a lacto-ovo vegetarian or pescatarian diet as it’s easier to obtain nutritional needs. Either way, including more plant-based meals and opting for more plant-based proteins and reducing your meat intake will have a beneficial effect on your health and may reduce the risk for certain types of cancers. 

If a predominantly plant-based lifestyle sounds daunting, start with one day in the week by adding brown lentils to a mince dish, chickpeas to a curry or beans to a soup.

Whatever you decide to do, please speak to a registered dietitian before embarking on a new diet to assist in meeting your individual needs.

Header image by Adocbe Stock