How can diet link to disease

There is accumulating scientific evidence on the health advantages of a whole food plant-based (WFPB) diet, with researchers claiming that such a diet could result in preventing around eleven million premature deaths from heart disease, diabetes and other chronic conditions globally each year.

A WFPB diet can help prevent heart disease and certain cancers – the key point is that the evidence relates to a WFPB diet, not just a vegan diet, which can rely heavily on processed meat alternatives.

The term WFPB diet was coined by Dr T Colin Campbell, a scientist with a career spanning over 60 years, whose focus has been on the association between diet and disease, particularly cancer.

Dr Campbell recommends that all vegetables are eaten freely and in plentiful amounts, including dark green leafy vegetables; whole fruits; legumes, which include beans, chickpeas and lentils; nuts and seeds, and optional fortified non-dairy milk. Oils and processed foods are not included in a WFPB diet.

Coronary heart disease (CHD) causes the death of almost 74,000 people in the UK each year and risk factors include raised blood pressure (BP), also known as hypertension (HTN), and high cholesterol.

A WFPB diet contains foods known to maintain a healthy BP and these include wholegrains and vegetables rich in nitrates. Nitrates in vegetables maintain the health of arteries and widen the blood vessels so that blood is able to flow freely, thus lowering BP.

Top sources of plant nitrates are rocket, rhubarb, coriander, spring greens, basil, beetroot greens and beetroot, and their function is thought to be boosted further with the addition of balsamic vinegar.

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Salt

Salt is a major risk factor for HTN and while we need a little salt in our diets, we generally exceed the recommended upper limit of 6g daily – that’s just one teaspoon. The main dietary sources tend to come from processed and prepared foods, meat, and salt added to cooking or at the table.

By sticking to a WFBP diet you will naturally be avoiding added salt and will easily fall under the recommended daily limit.

In addition, many plants are a great source of the mineral potassium, which relaxes the blood vessels in our arteries, thereby lowering BP. Great sources of potassium include dark green leafy vegetables, sweet potato, avocado and bananas.

Saturated Fat

Saturated fat, found mainly in animal products, is the main driver for increased blood cholesterol – a risk factor for CHD – as it stimulates the production of LDL (bad cholesterol) and also reduces its turnover so that it remains in the bloodstream.

Studies have shown that unsaturated fats do the opposite and that WFPB diets can reduce cholesterol as effectively as first line statins and without the side effects. How do they do this? Plants contain sterols and these bind with dietary cholesterol to prevent its absorption.

The recommended intake of sterols is 2-3g daily and this is easily achieved on a WFPB diet. In addition, the high levels of fibre reduce fat absorption by binding with it and removing it from the body.

Although the calorie and fat content of nuts, for example, are high, not all of it is absorbed by the body because a proportion of it follows the fibre out in your stools.

Essential Fatty Acids

There are two really important components in a WFPB diet and these are the essential fatty acids – omega-3 and omega-6.

Our bodies are unable to make them, which means that we need to get them from our diets and the anti-inflammatory omega-3s are particularly important in terms of disease prevention.

They are found in higher quantities in animal products, but we can get small amounts from walnuts, chia/flaxseeds and dark green leafy vegetables.

Vegans may benefit from adding an omega-3 supplement containing 400-500mg of EPA/DHA, although more long term studies are needed to help clarify this.

Cancer

In terms of cancer prevention, it is important to clarify that not every cancer is linked to diet and lifestyle, but there are 13 different types of cancer known to be linked and these include breast, bowel, liver, thyroid, pancreas and oesophageal cancers, as well as ovarian and cervical.

The World Health Organisation (WHO) classed processed meat as cancer causing in 2015 and red meat as probably causing colorectal cancer, yet, unlike cigarettes, there are still no health warnings on processed meat packaging.

Cancer accounts for 42% of deaths before the age of 75 and lung, breast, prostate and colon cancers account for more than 50% of these deaths, 40% of which are thought to be preventable (Cancer Research UK).

The World Cancer Research Fund updated their cancer prevention recommendations in 2018 to include limiting processed meat/ foods, fast foods and red meat, and eating a diet rich in fruit and vegetables, wholegrains and beans.

There is a large body of evidence supporting WFPB diets for cancer prevention and also improving outcomes after diagnosis. Red fruit and vegetables contain lycopene, which is a powerful antioxidant and it becomes more available when the fruit/veg is cooked.

Berries contain the highest amount of antioxidants of all fruit and are a really important addition to the diet.

Cruciferous vegetables, including cauliflower and broccoli, are thought to be particularly beneficial as they are broken down into compounds with anti-inflammatory/anti-bacterial effects and may help prevent DNA damage, however more studies on humans are needed.

Turmeric contains the substance curcumin, which helps prevent DNA damage and so may inhibit the initiation steps of cancer and also cancer cell growth. It can be added to porridge, smoothies, mashed potato and curry/chilli dishes.

There is also strong evidence regarding WFPB diets and type 2 diabetes, dementia and fertility. If you want further advice relating to anything discussed in this article or the above conditions, you can contact me via my website www.tiptoptum.com or @tiptoptumdietitian on Instagram.

About Lisa Simon

After qualifying as a registered dietitian in 2014, Lisa Simon worked for five years in the NHS before leaving to start her own business, specialising in plant-based nutrition. She is bringing up her 16-month-old son plant-based and has a keen interest in the effects of such a diet on fertility and sports performance and recovery.