High carb diets again linked to increased risk of breast cancer

Previously on this site (for example see here) I have written about the role that certain carbohydrate foods appear to have in the development of breast cancer. Foods that are disruptive to blood sugar (high glycaemic index) foods have been implicated here. Also when high GI foods are eaten in quantity, they tend to have what is known as high ‘glycaemic load’ (GL – calculated by multiplying the amount of carbohydrate in a portion by the GI and then dividing the result by 100). High GL diets have been implicated as a risk factor for breast cancer too.

A study just published has added further evidence suggesting that carbohydrate foods can increase a woman’s risk of breast cancer [1]. In this study, more than 61,000 women were followed for over a 17-year period. Overall, higher GL diets were associated with an increased risk of breast cancer (though higher carbohydrate and higher GI diets were not).

The researchers went on to look at the relationship between carb intake and different types of breast cancer. Breast cancer is usually ‘hormone dependent’ (hormones can trigger and drive the development of the tumour), and can express receptors to the hormones such as oestrogen and/or progesterone. The researchers found that cancers that express oestrogen receptors but no progesterone receptors had strong links with carbohydrate intake.

High carbohydrate, high GI and high GL diets were associated with an increased risk of this sort of breast cancer of 33, 44 and 81 per cent respectively. The authors conclude that their findings suggest that a high carbohydrate intake and diets with high glycaemic index and glycaemic load may increase the risk of developing oestrogen positive/progesterone negative breast cancer.

Breast cancer risk has been linked to higher levels of the hormone insulin (see here for more about this). When insulin levels go up, so can the levels of related substances known as ‘insulin-like growth factors’, and these have also been implicated in the development of breast cancer.

Conventional nutritional advice has encouraged us all to eschew fat and embrace the high-carb ideal. The problem is, that this may well be contributing to our disease burden, including with regard to breast cancer risk. A better diet, I suggest, would be one which is lower in carb. This diet might be more in keeping with the diet we evolved on. Meat, fish, eggs, nuts, fruit and vegetables (other than the potato) should form the core foods in the diet, I think. Interestingly, diets with higher animal foods in them have been linked with a reduced risk of breast cancer (see here)

Any real link here may not be due so much to some particular nutritional goodies animal foods have to offer. It might have more to do with the fact that the more such foods are eaten, the less tendency there is to fill up on carbs that have disastrous consequences for health.


1. Larsson SC, et al. Glycemic load, glycemic index and breast cancer risk in a prospective cohort of Swedish women. Int J Cancer. 2009;125(1):153-7

4 Responses to High carb diets again linked to increased risk of breast cancer

  1. Helen 18 July 2009 at 12:27 am #

    You certainly won’t find any of this information on the breast cancer info infact they almost frown at a low carb diet and i have heard one cancer expert say that no food can give you cancer! and no vitamin, mineral or food can cure it only chemo therapy will cure cancer. I absolutely dispair for women unfortunate enough to have to put up with this unenlightened bull from so called experts. For all those poor women given no choice but chemo or radiation after surgery there are other alternatives only your doctor isn’t allowed to tell you but most don’t even give you enough time to look at or discuss anything else before they chop and burn – they do have a lot to answer for and no real out comes worth a damn as support for their outrageous claims! I can’t stand that patronising attitude they get when anyone even suggests there may be alternatives and there are many in fact that actually work by building the strength of the body at a cellular level maybe health not wealth should be their priority.

  2. Trinkwasser 20 July 2009 at 11:24 pm #

    I understand cancer cells are principally fuelled by glucose so this is not really surprising. Probably by keeping the glucose levels down you are at worst preventing the cancer from proliferating so rapidly and at best giving your immune system a better chance of blatting runaway cells before they get to form a tumour

  3. Angela 3 August 2009 at 2:14 pm #

    Thank you very much for your words of advice. I shall suggest the same to my aunt who recently got diagnosed with breast cancer.



  1. Insulin again implicated in breast cancer | Dr Briffa's Blog - A Good Look at Good Health - 5 April 2013

    […] Previous research, has linked the consumption of the most blood sugar disruptive carbohydrates (high glycaemic index carbohydrates) with an increased risk of breast cancer. […]

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