You see, I’m done. Or at least I think I’m done. I have just finished an 8-week course on Cancer Prevention & Survivorship via the University of Winchester, and you’d think I’d be elated on learning about all this emerging science and tools we have to fight this terrible illness.
But no, I’m actually furious. Why, you may ask? Because most of it will fall on deaf ears.
As Dr Michael Greger said in one of his famous talks: a lot of doctors do not even mention to patients how they could improve their health as they know that the patients won’t change anything with regards to their lifestyle.
I’ve been on the receiving end of this for the past 9 years.
Yes, 9 years of being mocked at, laughed at, ridiculed, just because I’m trying to WARN people. I will present the 6 biggest take-aways from the course, all of them easy to change and yet the grief I get on the back of pointing these things out is beyond comprehension. So, I often stop talking.
And then we get some people who still don’t know about the link between red meat and cancer. As sad as it sounds but we tried to warn you. But there’s just sometimes no way of getting through the pre-conceived habitual barrier of: ‘La la la, I don’t want to know’ attitude. People don’t know what they don’t know because they DO NOT WANT TO KNOW. Good grief.
Anyway, if you are still here, reading this, great. If you want to know more, keep reading.
First, let’s shine some light on the subject.
Cancer is the second most common cause of death globally (after heart disease), with 19 million new cases and an estimated 10 million deaths annually[1].
In the UK, one in 2 people born after 1960 will develop cancer in their lifetime[2].
The commonest cancer types are lung, breast, prostate, and colorectal cancer.
Cancer takes decades to develop and the initial trigger, usually genetic damage, or mutation to a single cell, may occur in childhood and later give rise to cancer in adulthood.
40-50% of CANCER CASES COULD BE PREVENTED.
What are the major lifestyle factors that contribute to increased risk of developing cancer:
Smoking, including parental or passive smoking
Higher parental age
Higher BMI and waist circumference
Alcohol
Lack of exercise
Psychological stress, including early in life.[3]
If you want to study in detail all of the above (and more), please sign up to this course, it’s fascinating.
However, what I would like to focus on are these 6 points, things that people don’t know or argue about, but mostly disregard or ignore.
Buckle up.
Processed and red meat
Processed meat is classified by WHO as a group 1 carcinogen (it causes cancer) and red meat as a group 2 carcinogen (probably causes cancer)[4]. This is mainly in relation to colorectal cancer, but consumption of red and processed meat has also been linked to increased risk of other cancers, including lung, breast, pancreatic, oesophageal, nasopharynx and stomach.
The main reason for the cancer-causing properties of processed meat are the nitrites and nitrates used to preserve the meat. These are converted in the gut to N-nitroso compounds, including nitrosamine, that damage DNA and cause cancer.
Here is another biggy: Haem iron (I have daily conversations about it). Yes, haem iron is easier absorbed than the one from plant-based sources but Haem iron in both processed and red meat also generates N-nitroso compounds and in addition is a pro-oxidant creating oxidative stress, which can damage cells and DNA.
Cooking meat (both red meat and poultry) at high temperatures (think: barbeque) generates carcinogens, which are also implicated in cancer development. We knew about this long before we went vegan, that’s why our barbeque ended up where it belonged all along: in the bin.
Of note, nitrates contained in vegetables are not converted to N-nitroso compounds, because the presence of vitamins and phytonutrients within the food prevent the conversion.
If you worry about iron and whether you can get enough of it on a plant-based diet, don't! Check out this quick cheat-sheet instead, it’s brilliant!
Animal protein
Another mechanism that contributes to the connection with cancer, apart from the points mentioned above is that animal protein increases the level of insulin-like growth factor (IGF-1) in the body[5]. Elevated IGF-1 levels are associated with an increased risk of several cancers. This association is not seen with the consumption of plant protein. Vegans have the lowest levels of IGF-1, when compared to other diet patterns[6].
Those eating a diet consisting of more than 20% protein, particularly animal protein, had a 4x increased risk of death from cancer compared with a low protein diet of less than 10% protein. The association here was lower levels of IGF-1[7].
Processed foods and soy
Now here it becomes interesting. I often hear from people telling me that tofu or tempeh is ‘processed’. Well, almost anything is somehow processed. Those people who talk so openly about tempeh being highly processed are usually those who have never made it from scratch.
And yet, the victimised soy (ideally, for argument’s sake, you’d eat edamame as it’s the least processed) is one of the best plants to eat from a health point perspective.
For example, with regards to breast cancer prevention, it seems that swapping dairy for soya-derived foods and drink may be a good option. A meta-analysis of observational studies, regular consumption of tofu reduced the risk of breast cancer by around 12%[8].
Now, going back to ultra-processed foods, Houston, we have a problem. Yes, there is an emerging link to cancer and their consumption[9][10], however, what’s worse is that more than 50% of foods bought in UK and US supermarkets are classified as ultra-processed!
Why are they so bad? The potential mechanism includes an increased risk of obesity. And, OBESITY IS NOW A LEADING CAUSE OF CANCER. Also, various additives, low nutrient content and lack of fibre, antioxidants and phytonutrients play a role.
Fruit and vegetables
After coming across such “gems” like the book called ‘The Plant Paradox’ and talks about oats being poisonous… I am not even sure if people know whether eating fruit and vegs is still considered good or bad. Do we?
Anyway, for those who will continue to plough through the boring odd apple or so, what I found interesting during my course is the amount of fruit and veg you need per day to significantly reduce the risk of cancer by around 13%.
Brace yourself, it’s a lot. You need 600g per day.
With regards to cancer the consumption of green-yellow vegetables and especially cruciferous vegetables (they have tumour suppressing activity) shown particular benefits. The reason for this association will be the high fibre intake and high intake of antioxidants and other phytochemicals that are known to prevent cancer.
Not all plant-based or meat free diets are healthy though.
This point is probably obvious, but heck, I’ll say it again.
You see, when I talk about plant-based eating I talk about whole-food mostly homecooked meals centred around fruit, veg, legumes, whole grains, nuts and seeds.
I do not talk about processed foods, refined grains, and sugary drinks. These types of diets may actually increase the risk of cancer.
Now, for those who cannot possibly imagine living without consuming animals, aim for a predominantly >85% plant-based diet. What does it mean?
Reduce your intake (per week) to:
1 portion of red meat (98g)
2 portions of poultry (200g)
3 eggs [11]
What is NOT preventative medicine?
Tests or screening for cancer (e.g., mammography for breast cancer, prostate-specific antigen for prostate cancer, and faecal immunochemical test and colonoscopy for colon cancer) are not considered as truly preventative as they are detecting cancer at an early stage and therefore are considered REACTIVE.
Lifestyle (or preventative) Medicine focuses on lifestyle modifications.
And knowing that some cancers are often an accumulation of a long-time underlying cause, we’re talking here of adopting a healthy diet and exercise habits as early as possible, from childhood onwards.
Alcohol
I think we all suspect that alcohol is not beneficial for our health, to say the least. But has it been really spelled out for you that there is a direct link to cancer? In fact, that it is an ESTABLISHED CAUSE OF CANCER? That the safest limit for health is ZERO? No, I didn’t know this either.
The lack of public awareness is scary. And yet there will be some fools running around talking about the dangers of seed oils while staying quiet on the topic of alcohol!
Okay, this is it. Of course, we could spend hours talking about so many other food staples and dive into details of various adaptogens etc. But if we address the cow in the room as opposed to arguing about the omega-6, we might have a better chance of playing the epigenetic card in our favour.
Now you know.
The ball is in your court.
The new intake for Lifestyle Medicine for Cancer Prevention and Survivorship via the University of Winchester starts in October 2024.
REFERENCES
[1] Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021;71(3).
[2] Smittenaar CR, Petersen KA, Stewart K, Moitt N. Cancer incidence and mortality projections in the UK until 2035. Br J Cancer. 2016;115(9).
[3] Commun Biol 5, 565 (2022). https://doi.org/10.1038/s42003-022-03521-7 Medicina (Kaunas). 2022 Feb 5;58(2):242. doi: 10.3390/medicina58020242.PMID: 35208566; PMCID: PMC8879766.
[4] IARC. IARC Monographs evaluate consumption of red meat and processed meat. World Health Organisation. 2015.
[5] Levine ME, Suarez JA, Brandhorst S, Balasubramanian P, Cheng CW, Madia F, et al. Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metab. 2014;
[6] Allen NE, Appleby PN, Davey GK, Kaaks R, Rinaldi S, Key TJ. The associations of diet with serum insulin-like growth factor I and its main binding proteins in 292 women meat-eaters, vegetarians, and vegans. Cancer Epidemiol Biomarkers Prev. 2002;
[7] Cell Metab. 2014 Mar 4;19(3):407-17. doi: 10.1016/j.cmet.2014.02.006. Cancer Res (2020) 80 (18): 4014–4021. https://doi.org/10.1158/0008-5472.CAN-20-1281
[8] Wang Q, Liu X, Ren S. Tofu intake is inversely associated with risk of breast cancer: A meta-analysis of observational studies. PLoS One. 2020;
[9] Fiolet T, Srour B, Sellem L, Kesse-Guyot E, Allès B, Méjean C, et al. Consumption of ultra-processed foods and cancer risk: Results from NutriNet-Santé prospective cohort. BMJ. 2018;
[10] Chang K, Gunter MJ, Rauber F, Levy RB, Huybrechts I, Kliemann N, et al. Ultra-processed food consumption, cancer risk and cancer mortality: a large-scale prospective analysis within the UK Biobank. eClinicalMedicine [Internet]. 2023;56:101840. Available from: https://www.sciencedirect.com/science/article/pii/S2589537023000172
[11] Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019 Feb 2;393(10170):447-492. doi: 10.1016/S0140-6736(18)31788-4
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