The nexus between Nutrition and Breast Cancer
Food is the most essential requirement for sustenance of human life. Throughout history food has acted as a catalyst for societal transformation, societal organization, development and expansion. The month of October is the breast cancer awareness month and it is imperative to understand the nexus between the food we eat and breast cancer, so that we stay informed and reduce the chances of developing breast cancer while also knowing how best we can take care of those who have breast cancer. The Agric, Food and Beverages (AFB) vision magazine editor Caroline Chiimba (CC) interviewed Nutritionist Lorraine Maunze (LM) to unpack the topic. Below is the interview:
CC: Can you explain in detail the nexus between nutrition and Cancer
LM: The connection between nutrition and cancer has been well documented. Research has shown that certain foods can predispose an individual to cancer. This is because being overweight or obese is one of the biggest risk factors for developing cancer. Consequently, consuming a lot of low-fibre (highly processed cereals/grains), high fat foods (fast food, fried food) and food high in sugar (soft drinks, sweets, chocolates etc) will result in weight gain thus increasing the risk of developing cancer.
Being overweight or obese increases cancer risk due to the changes that occur in the body due to weight gain such as higher than normal levels of insulin, insulin-like-growth hormone, sex hormones and long lasting inflammation.
The Cancer Association of Zimbabwe (CAZ) goes on further to list low consumption of fruits and vegetables and consuming a diet rich in nitrates and nitrites as factors that can predispose one to increased cancer risk. Nitrates and nitrites are found in cured or processed meats like bacon, sausages and ham.
CC: From a nutritional perspective, what triggers breast cancer?
LM: According to the study on Nutrigenomics and Breast Cancer, alcohol intake was widely recognized as a consistent dietary factor associated with breast cancer risk since alcohol consumption results in the development of highly dense glands. Saturated fat intake (cholesterol) was also associated with increased breast cancer risk as was intake of red meat. Low dairy intake of less than 400g/day and consumption of more than 5 eggs a week increased the risk of breast cancer. Evidence around the consumption of fruits and vegetables and associated cancer risk revealed that certain fruits like citrus fruits conferred a protective advantage although study findings were dependent on study design and type of fruit.
Citation: Sellami M, Bragazzi NL. Nutrigenomics and Breast Cancer: State-of-Art, Future Perspectives and Insights for Prevention. Nutrients. 2020 Feb 18;12(2):512. doi: 10.3390/nu12020512. PMID: 32085420; PMCID: PMC7071273.
Breastmilk and the associated action of breastfeeding has also been shown to reduce the risk of developing breast cancer. As a country, in line with WHO guidance we advocate that breastmilk is the best food for the baby during the first six months of life and there is mounting evidence that shows breastfeeding significantly reduces the risk of developing breast cancer due changes in sex hormones like oestrogen during lactation which delay menstrual periods and consequently reduce women’s lifetime exposure to sex hormones that promote breast cancer cell growth.
CC: There is what we call anti-cancer diet. Kindly tell us more about it, what it entails and how it can be achieved
LM: An anti-cancer diet is a diet that minimizes the risk of developing cancer. This diet will typically consist of all the opposite factors that are associated with increased cancer risk. An anti-cancer diet would therefore consist of:
- A high fibre diet – unrefined and whole grain foods such as high fibre maize meal, unrefined cereals, brown or whole wheat bread, oats, brown rice, fresh fruit, and vegetables (with skin and peels on if possible), dried beans and lentils
- A low-fat diet – consuming moderate amounts of fat that are mostly in the form of unsaturated oils like those found in nuts and seeds, avocado pear, olives, olive oil and grape seed oil is beneficial
- A low sugar diet – stay away from foods that are refined and contain a lot of sugar
- Consume a wide variety of fruits and green leafy / cruciferous vegetables in raw form, if possible, with skin and peels intact (as a lot of nutrients are found just beneath the peel). Fruits provide valuable micronutrients some of which have antioxidant properties and also provide much needed roughage
- Reduce alcohol consumption – not more than one glass /day for women and 2 glasses per day for men.
- Reduce consumption of red meat as well as processed / cured meat
- Consume lots of water
- Consume soya-based foods (soya beans, tofu) – the CAZ states that breast cancer incidence in countries such as Japan that consume a lot of soy based products is low
Anti-cancer diets need not be expensive. Following our traditional diets of consuming lots of water, consuming unrefined /straight run cereals, and consuming plenty of indigenous fruits and vegetables while maintaining active lifestyles is beneficial. People should not shun traditional or indigenous foods or view them as inferior. A lot of the pro-healthy shops are selling traditional foods just packaged differently at a premium.
CC: People are encouraged to eat more fruits and veggies, how do these prevent or reduce chances of cancer? What are their nutritional benefits?
LM: Fruit and vegetables are rich in antioxidants, fibre, minerals, phytochemicals and vitamins which reduce cancer risk. Fruits and vegetables while being micronutrient rich are generally low in the amount of energy (kilojoules) that they provide to the body, thus they help to maintain a healthy body weight consequently preventing excess weight gain.
CC: What kind of diet is recommended to prevent breast cancer recurrence?
LM: Diets to prevent breast cancer recurrence would focus on the dietary recommendations cited earlier.
- High-fibre foods
There is some evidence that fibre may reduce the risk of breast cancer recurrence, but more research is needed.
High-fibre foods tend to be lower in calories and can help you feel full up for longer thus they prevent weight gain. High fibre foods include:
- Wholegrain foods such as brown rice, oats, wholewheat bread
- Pulses such as lentils and beans
- Starchy foods such as potatoes and sweet potatoes, preferably with their skins on
- Vegetables and fruits
- Saturated fat
As with fibre, there is some evidence that saturated fat may affect the risk of recurrence, but again more research is needed.
It’s a good idea to limit the amount of fat you eat, particularly saturated fat, because it increases the risk of conditions such as heart disease and leads to weight gain.
Foods that are high in saturated fat include:
- Fatty cuts of meat
- Processed meats such as sausages
- Full-fat dairy products, including whole milk, cream, and hard cheese
- Chocolate, biscuits, and cakes
Try to replace saturated fats with healthier unsaturated fats found in foods such as:
- Olive oil, rapeseed oil and their spreads
- Oily fish such as salmon and mackerel
- Nuts and seeds
If you’re having foods that contain saturated fats, choose ones with lower saturated fats. For example, choose lower-fat dairy products such as skimmed milk, low-fat yoghurts, lower-fat cheeses like feta, and leaner meats such as chicken and turkey.
- Soy and foods that contain phytoestrogens
Soy foods such as soy milk and tofu contain natural compounds called phytoestrogens. Foods such as chickpeas and linseeds also contain phytoestrogens.
Phytoestrogens have a chemical structure that is similar to the hormone oestrogen. As oestrogen can stimulate some breast cancers to grow, some people worry whether foods or supplements containing phytoestrogens might have the same effect as oestrogen and increase the risk of recurrence.
Current evidence suggests that a diet containing naturally occurring phytoestrogens is safe if you’ve had breast cancer and may be beneficial.
- Organic foods
Some people choose to eat organic foods as a way of reducing pesticides in their diet. However, no association has been found between eating an organic diet (before or after diagnosis) and the risk of breast cancer recurrence.
The term ‘superfood’ has been used to describe foods that are apparently beneficial for preventing or treating a range of health conditions.
So-called ‘superfoods’ include:
- Green tea
However, it is important to note that there is no evidence that any single food can reduce the risk of breast cancer developing or coming back in someone who has been diagnosed. Source: www.breastcancernow.org
CC: What are the nutritional needs of a breast cancer patient
LM: A balanced diet is especially important when you have breast cancer or any illness. Proper nutrition helps your body heal from cancer itself and side effects that arise from cancer treatment such as nausea, vomiting, mouth sores, and low appetite. Proper nutrition also helps to maintain a healthy immune system, maintain body strength and reduce fatigue.
There is no specific diet that is recommended for people with breast cancer as nutrient needs vary depending on many factors that include other medical diagnoses, your body weight, nutrient deficiencies, medications, and any symptoms that you’re currently experiencing. A patient’s healthcare team, including a registered dietitian should help a patient come up with an appropriate eating plan specific to the patients’ needs and overall health.
However, general recommendations to maintain overall health while living with breast cancer are highlighted below:
- Consume whole, nutrient-dense foods like fruits and vegetables, whole grains, legumes, protein sources like chicken and turkey, fatty fish like trout or salmon, and plant-based proteins sources like lentils and nuts
- Include foods high in healthy fats and protein. If you need to maintain or gain weight, incorporate sources of healthy fat like nuts and seeds, avocados, and olive oil as well as protein sources like eggs, chicken, lentils, and fish. Protein-rich foods are especially important for maintaining muscle mass.
- Try blended liquids – milkshakes, smoothies, juices, or soups for those times when you do not feel like eating solid foods
- Consume food rich in fibre like whole grains, flax seeds, legumes, vegetables, and fruits to treat constipation
- Eating foods that contain phytochemicals present in plant-based food may help your body fight cancer.
- Research reveals that when people living with breast cancer eat more fruits such as blueberries, oranges, and vegetables (especially green leafy or cruciferous vegetables), their risk of survival may be higher.
Avoid alcohol, spicy and acidic foods, red and processed/cured meat, sugary foods including soft drinks and refined/processed cereals.