Why should we eat vegetables ?

Variety-Vegetables

With LCHF eating really taking off here in South Africa, everybody is suddenly an expert, whether it’s to promote the way of eating or to condemn it. It seems to have given rise to an opportunity for those requiring some form of reinforcement for their egos to create social media pages under the guise of being exceptionally knowledgeable on the topic and in an position to dish out advice to slavish ( sadly ) followers.

What is a concern, is that although there is plentiful well meaning advice that is often correct, there is also a lot of incorrect advice born of personal opinion or assumption rather than fact. Really frightening however , is the advice being put out by, bluntly put, charlatans !

I think this is a good topic for a number of articles but today I want to address the importance of eating vegetables.

This is a question that seems to be popping up with increasing frequency and I suspect stems from members of one of the above mentioned social media groups being informed that vegetables are not a dietary requirement.

I have yet to understand the reasoning behind this advice because all expert opinion I have read , whether for or against LCHF eating , agree that vegetables should form an abundant part of the diet.

Let’s have a look at a few points.

One of the arguments against vegetables is that we can obtain all the nutrients our bodies require from animal organ meat.  While this is true, it must be emphasised that pasture raised hormone free animals are nutrient dense and not their commercial lot fed counterparts.

These are the proven nutrients that we know we cannot live without but recent research is showing a whole class of nutrients that are increasingly important. These nutrients may not be essential to life but in a number of studies are shown to reduce oxidative damage, inflammation as well as reduce our risk of death.

These are called phytonutrients or antioxidants.  Phytonutrients are plant- and fruit-based compounds that are antioxidants.antioxidants-fruit

Why are these antioxidants important? Well , to understand this we need to first understand what free radicals are .radicals 2

Dr Mercola summarises it nicely “ Free radicals are a type of a highly reactive metabolite that is naturally produced by your body as a result of normal metabolism and energy production. They are your natural biological response to environmental toxins like cigarette smoke, sunlight, chemicals, cosmic and man made radiation, and are even a key feature of pharmaceutical drugs.

Your body also produces free radicals when you exercise and when you have inflammation anywhere in your body.

Free radical molecules are missing one or more electrons, and this missing electron is responsible for biological oxidation. The incomplete molecules aggressively attack other molecules in order to replace their missing parts. These reactions are called “oxidation” reactions. Oxidation is called “biological rusting,” an effect caused by too much oxygen in your tissues.

Free radicals steal electrons from the proteins in your body, which badly damages your DNA and other cell structures. They can create a “snowballing effect” – as molecules steal from one another, each one becomes a new free radical, leaving a trail of biological carnage.

radicals

Free radicals tend to collect in cell membranes (lipid peroxidation), which makes the cell lipids prone to oxidative damage. When this happens, the cell membrane becomes brittle and leaky, causing the cell to eventually fall apart and die.

Free radicals can severely affect your DNA by disrupting the duplication of DNA, interfering with DNA maintenance and breaking open or altering its structure by reacting with the DNA bases. Free radicals are linked to over 60 different diseases, including cancer , Parkinsons disease , Alzheimer’s and atherosclerosis , to name a few.”

Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-“stealing” reaction. The antioxidant nutrients themselves don’t become free radicals by donating an electron because they are stable in either form .They act as scavengers, helping to prevent cell and tissue damage that could lead to cellular damage and disease.

The topic of free radicals and anti oxidants is a topic all on its own – for now let’s leave it at one of the important reasons for eating vegetables.

Boar-HuntThe second argument is that our ancestors didn’t eat vegetables so why should we? This argument does not really hold water . If you look into this you will find that most of our ancestors ate plants.  There are exceptions of course , like the Inuit who ate a lot of meat or fish, sea mammals. Of course, there’s been some research recently that suggests they actually ate more plants than we thought they did. But there are always outliers. When you look at the average hunter-gatherer society, you actually find that they ate a lot of plants and a huge diversity of plants. For example, the Alyawarra tribe in Africa ate 92 different species of plants.

Compared with primates, humans have many more copies of a gene (AMY1) essential for breaking down calorie-rich starches. The ability to digest starch, along with the discovery of fire and cooking, gave humans a new food source that allowed us to thrive even in marginal environments. Some scientists have even argued that consumption of starch, along with meat, was primarily responsible for the increase in our brain size.(1)

Anti oxidants and vitamins aside, arguably the most important role of vegetable is to provide the gut microbial with fibre.

MicrobiotaGraphic_en72When we eat the soluble fibres found in whole plant foods, the bacteria in our gut ferments these fibres into short-chain fatty acids like  butyrate, propionate, and acetate, and greater amounts of fibre consumed will lead to greater short-chain fatty acid production.  These are extremely beneficial energy sources for the body, including the cells that line the digestive tract and help to maintain a healthy gut barrier.  Short-chain fatty acids are also essential for regulating metabolism and they aid in the absorption of minerals, such as calcium, magnesium, copper, zinc, and iron.  Healthy gut bacteria have many other important beneficial effects in the body, such as aiding and regulating the immune system.  Naturally occurring soluble fibres are very important for feeding the friendly bacteria that live in our guts.

Justin Sonnenburg of Stanford University does ground-breaking research using germ-free mice, where he implants in them various species of gut microbes to see what happens.  He observes that when mice eat a typical chow such as cracked corn, it feeds not just calories to the mice, but fibers to the microbes in the colon. As the microbes munch those fibers, they produce beneficial byproducts, such as vitamins and fatty acids, that in turn promote “our” health. 

Have a read here – Fiber & “Starving our Microbial Self”

One of the biggest culprits in the rise of chronic disease seen in the last 50 years is the decrease in fibre consumption.(2)

Dietary fibre is inversely correlated with the prevalence of type 2 diabetes (meaning the lower your fibre intake the higher your risk of developing T2D

Fibre rich diets have also been shown to reduce the risk of colorectal, liver and pancreatic cancer as well as decrease cardiovascular disease and overall inflammation.

Prospective studies have confirmed that the higher your intake of fibre, the lower your inflammation (as measured by C-reactive protein).  And in fact, a new study showed that the only dietary factor that correlated with incidence of ischemic cardiovascular disease is low fibre intake.

In my opinion this should be sufficient reason to add a good portion of vegetable to your plate !

eat veggies

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