Nutrition - Prostate cancer

Tuesday 08 May 2018

Amongst all of the blogs that I have written to date it struck me that I have not focussed on prostate cancer and the research that shows the benefit of a healthy diet. This coupled with some specific foods that appear to have positive benefits. I suppose also what prompted me was the recent article in the newspapers stating that omega 3 was not good for prostate health.  Perhaps a bit more detail would be useful for those that it may affect. I have had so many emails and phone calls from men taking omega 3 it seems right to look at this research a bit more.

Omega 3 and prostate cancer
The recent report was by the Fred Hutchinson Cancer Research Centre in Seattle and was published in the Journal of National Cancer Institute. It claimed that omega 3 was linked to an increased risk of prostate cancer.

On further study it is evident that this trial has many limitations. Firstly it only discussed the correlation and correlation does not equal causation. It does not include any information about how omega 3 intake was achieved, whether through diet or supplementation. It was lacking control, as participants were asked to complete a self -administered questionnaire concerning alcohol intake and smoking habits amongst other factors. Nobody was asked about diet or fish oil levels. It is also unclear from the results exactly how high levels of omega 3 could increase the risk of prostate cancer.

So considering this, stating fish oils increase the risk of prostate cancer is unhelpful and unproven. The results of this recent study should be carefully considered, but should not negate the evidence showing the safety and benefits associated with omega 3 consumption from so many other more robust studies. They found that omega 3 may support the following;

• Induced apoptosis (cell death)
• Suppressing cancer initiation
• Decreasing rates of cancer progression.
• Helping to prevent cancer spreading.
• For more on the benefits of omega 3 and health see my previous blog

So back to prostate cancer….
Early research on Prostate cancer would suggest that elevated levels of testosterone was one of the drivers for its development. This is not exactly accurate because it appears that oestrogen actually converts ‘safe’ testosterone into DHT, which is an extremely aggressive cancer causing agent.

So we could say that it is not testosterone but the presence of oestrogen that may be the driving factor.

This has been supported by more recent research that high levels of oestrogen seems to be one of the main precursors. For 15 years or more we have known that certain toxic chemicals mimic the action of oestrogen in the body and that these have been very damaging to male fertility. As a result many pieces of research, carried out by many Cancer Institutes in many countries, the conclusion has been that 13 different chemicals mimic oestrogen and have been linked to prostate cancer. Also it seems that men do make more oestrogen these days largely due to too much animal fat and dairy foods in the diet and drinking recycled water. These chemical oestrogens are known as xenoestrogens, once inside the body can act like oestrogen, some more aggressively than others. Understanding this gives us some clues as to how to help ourselves once prostate cancer has been diagnosed.

To support our bodies it is recommended that we eat a diet:

  • High in fresh fruits and vegetables, 8-10 portions a day.
  • High in fibre and whole grains. You should get sufficient fibre from having the recommended fruits and vegetables with 2 servings of whole grains or perhaps some beans or lentils.
  • Low in saturated fats from animal foods and high in essential fats from oily fish, nuts and seeds and their butters.
  • Minimum amount of simple sugars. Look out for hidden sugars and read labels.
  • To include protein from plant sources like peas beans lentils and nuts, as well as animal sources.

let’s look at some of these in more detail relating to prostate cancer.

We know that fresh fruits and vegetables are rich in vitamins, minerals and phytonutrients that support the body and the immune system and the more vibrant the colours the more phytochemicals are present. There are some specific nutrients that have been linked to being very beneficial for men with prostate cancer. These are namely Antioxidants, particularly lycopene, selenium and vitamin E also indoles, curcumin and polyphenols.

This is found particularly in cooked tomatoes and cooked tomato products like tomato sauce. Tomato paste, fresh soup, and tinned tomatoes. It works by acting as a strong antioxidant neutralizing free radicals that can cause tissue damage by binding and neutralising bad fats in the blood (see blog on FR ). It also inhibits the multiplication of cancer cells. The Harvard Medical School recommended that men should have 7-10 helpings per week which would reduce symptoms by 40%. They also found that men who consumed 30mg a day (equivalent to a large serving of fresh tomato soup) had 18% lower PSA levels than a control group. Lycopene can also be found in guava, grapefruit, papaya and watermelon. (note that there are some contraindications with grapefruit and some drugs so double check this with your consultant if you are on medication)

This appears to inhibit cellular changes that may lead to prostate cancer and also inhibit angiogenesis which is where cancer cells develop their own blood supply for nourishment. It is worth noting that plasma selenium decreases with age so this may be particularly pertinent to older men. The best food sources are Brazil nuts, seafood, and grains. The amount found in food depends on the  amount in the soil that the food is grown in. 2 brazil nuts will provide a whopping 200 mcg which is the recommended amount for men with prostate cancer. Quite a simple easy way to ensure good levels I would have thought.

Vitamin E
Vitamin E and selenium have been shown to work synergistically in reducing cancer risk. It has been shown to lower the rates of conversion from latent to aggressive forms. Sources include wheat germ, nuts, seeds, sweet potato and avocado. The recommended amount is 400 iu’s (international units) a day. This should not be difficult to achieve in a good mixed diet.

I have previously a blog on the benefits of indoles, curcumin, and polyphenols. Basically the indoles are found in the cruciferous vegetables like broccoli, cauli, Brussels sprouts etc. Curcimin is the compound found from the spice Turmeric and polyphenols are found in green tea. I will leave you to look at the links to the  blogs below.

Saw palmetto
A herb that you may have heard of, which has been well advertised for supporting those with prostate cancer is Saw Palmetto. This has been shown to reduce the size the size of an enlarged prostate and reduce the growth of normal or malignant prostate cells by slowing the conversion of testosterone to DHT. It has also been shown to inhibit the growth promoting effects of Insulin Growth factor (IGF-1) found primarily in dairy products. It is the fatty acid content of the herb that appears to be the beneficial part. It is worth noting that to date I am not aware of any scientific studies that support these claims except one published in 2001 in the Cell Biology International. It is recommended that men with cancer should take 120mg a day. If you do decide to take this then make your consultant aware as it may exclude you from any trials that may be available.

Blog originally written by Caroline, August 2013

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