Breast cancer, diet and recurrence: top four myths dispelled

PUBLISHED ON: 30 November 2017

We explore the main breast cancer diet myths around recurrence with a NHS dietitian Penny Klebe.

Diets recommended on the internet or in the media are not always based on good quality research. Make sure you check the facts thoroughly before following alternative and restrictive diets, as they could cause more harm than good. If you’re unsure, you can ask your GP to be referred to a dietitian. You can also find tips on healthy eating and living well after breast cancer in BECCA, Breast Cancer Care's free app.

1. Dairy

Do dairy products increase risk of breast cancer recurrence?

Myth: Dairy products including milk, cream and cheese increase the risk of breast cancer coming back.

Fact: There is currently no scientific evidence that dairy products increase the risk of breast cancer recurrence. However, maintaining a healthy weight after treatment can reduce the risk of breast cancer coming back.

Dairy products are an important source of protein, calcium and some vitamins. However, some dairy products are high in fat, which can contribute to weight gain. You may want to choose lower-fat alternatives such as skimmed or semi-skimmed milk and reduced-fat cheeses, and just eat high-fat foods in small amounts.

If you move to low-fat options, be careful additional sugars have not been added. This can often occur in yoghurts. High sugar content in your diet can also lead to weight gain. 

If you decide to follow a dairy-free diet, such as in a vegan diet, it’s important to make sure that you get enough calcium from other food sources. These could include tinned sardines or salmon (with bones), or for a vegan diet, dark green leafy veg like spinach and kale and foods fortified with calcium, including alternative dairy products like rice and soya milks.

2. Sugar

Does sugar feed breast cancer?

Myth: A diet without sugar reduces the risk of breast cancer coming back.

Fact: Experts agree that there is currently no evidence to suggest that following a sugar-free diet reduces the risk of breast cancer recurring. While the possible link between sugar in the diet and cancer is often talked about, the research so far has not shown evidence of a direct link.

However, eating large amounts of sugar contributes to weight gain, so it’s best to avoid eating sugary foods too often.

3. Organic food

Does organic food reduce the risk of breast cancer returning?

Myth: Non-organic food contains pesticides that increase your risk of breast cancer recurrence after a primary diagnosis.

Fact: While you may prefer to eat an organic diet, there is no evidence that this will reduce the risk of breast cancer coming back.

4. Soya

soy-breast-cancer-risk

Myth: Eating soya-based foods can increase the chance of breast cancer recurrence.

One nutritional issue of interest is the impact of soya products (which contain phytoestrogens) on breast cancer recurrence rates.

Fact: 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 female hormone oestrogen. As the hormone 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.

Phytoestrogens are also found in supplements including:

  • black cohosh
  • red clover
  • sage

These are sometimes taken to relieve hot flushes and other menopausal symptoms. However, these are not recommended because the evidence on their effectiveness and safety is limited and conflicting.

Find out more about diet, lifestyle and breast cancer recurrence

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Penny works as a Highly Specialist Nutrition Support Dietitian for the Kent Community Health NHS Foundation Trust.

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