This post was written by one of contributors; registered Associate Nutritionist (ANutr) – Rachael Matthews
The term ‘plant-based diet’ can encompass any diet that focuses on the intake of fruits, vegetables, wholegrains, nuts, and seeds whilst reducing your meat intake. These can range from veganism, which is the complete omission of any animal products, to ‘flexitarianisim’, a mostly plant-based diet with the occasional inclusion of meat, dairy and eggs, also dubbed as ‘casual vegetarianism’.
The plant based take-over
Over the past 5 years, the significant increase in people adopting plant-based diets in the UK has been nothing short of meteoric. Since 2014, the number of people turning to veganism has quadrupled (1), with 1 in 8 Britons now reporting they are vegetarian or vegan (2) . ‘Flexitarianism’ now accounts for almost 25% of the population (3). This number is set to rise exponentially, with vegetarians and vegans set to make up 25% of the population by 2025. Flexitarians will make up just under 50% of consumers (4).
Why are we switching to plant-based?
There are many reasons including religious, ethical, and environmental. One report 5 showed that in the UK:
- Health was the number one reason behind ditching meat, with 49% of respondents citing this as the reason
- Weight management was number two (29%)
- Animal welfare and environmental reasons were tied at number three (24%)
Plant-based products in industry
With the increase in people adopting a meatless lifestyle it’s not surprising that the demand for meat free products in the UK has soared by 987% since 2017 (6), with the UK launching more vegan products than any other market in the world last year (7). Supermarket giant Sainsbury’s noted a 65% increase year on year of plant based products (8) expanding their ‘Love Your Veg!’ range. M&S launched their ‘Plant Kitchen Range’ and even fast food chains such as McDonald’s and KFC have gotten in on the action.
So, with plant based products becoming more readily available you may be considering a switch to a meat free lifestyle for any number of reasons. Here, we will try to outline some of the health considerations, to guide you in making an informed choice, if you are considering taking the leap to adopt a plant-based lifestyle.
Plant based diets and protein
Protein is an essential building block, making up about 25% of each cell in our body. We need it for the repair and growth of muscles, tendons, bones, and hair. A common misconception around plant based diets is that they do not contain enough protein, or the right kinds of protein to sustain a healthy body – this is myth! Let’s delve a little further…
There are 2 types of protein: complete proteins and incomplete proteins.
A complete protein is a protein source that contains all nine ‘essential’ amino acids. Amino acids are the building blocks of protein. An essential amino acid is one that we need but that our bodies cannot produce themselves, so we must get them through the foods we eat. Complete proteins are found mostly in animal based products such as meats 🥩, fish 🐟, dairy 🥛, and eggs 🥚. Plant-based sources include soy (tofu, tempeh, edamame beans, soy milk), quinoa, amaranth, hemp and chia 🌱.
An incomplete protein is one that contains some, but not all, of the 9 essential amino acids. Food sources of these include: grains, legumes, nuts, seeds, vegetables. Basically, most foods that make up a plant-based diet. With a plant-based diet excluding some of main food groups which provide complete protein sources (as mentioned previously; meat, dairy and eggs) it was previously thought that vegans/veggies need to be consuming complementary protein sources at every meal to maintain a heathy body, however this has been de-bunked repeatedly. It is now widely accepted that a plant-based diet that includes a wide variety of vegetables, nuts, seeds and grains will provide you with all of the essential amino acids and protein that you need.
Considering an items’ overall nutrient profile is important when making an informed choice, not just its protein content. For example, some animal based products may contain higher levels of salt, fat, and saturated fat versus their plant counterparts. Furthermore, plant based proteins contain phytochemicals, nutrients from plants that can ward off disease.
To summarise, not only can whole-food plant based diets provide enough protein, they may also be lower in fat/saturated fat versus their animal meat counterparts.
Plant-based diets and vitamins
Whole food, plant based diets may be the optimal diet to ward off certain cancers, diabetes and obesity versus a standard ‘western diet’ (9). However, vegetarians and especially vegans may need a little more planning when it comes to getting enough of the following minerals and vitamins: iron, calcium, selenium, vitamin D, vitamin B12, and omega–3 and omega-6 fatty acids.
Vitamin B12 💊 – an essential vitamin for the metabolism of every cell in the human body, it is involved in the production of red blood cells and nerve cells. B12 is found only in animal products and is absent from plant-based foods, unless they have been fortified. Plant based products such as; soy-milk, some breakfast cereals and some meat analogues can be fortified, always check the packaging. The amount of B12 each person needs depends on age and it may be necessary to supplement your diet with an oral B12 supplement, if recommended by your doctor or dietician.
Selenium 🤒– another essential mineral which cannot be produced by our bodies, selenium plays an important role as part of our immune system and is an antioxidant in low doses. This means it can protect our bodies against free radicals (foreign bodies caused by external sources such as smoking, pollution that can cause our bodies damage). Selenium is usually found in animal based products such as meats, eggs, and fish. The best sources within plant based foods are: brazil nuts, sunflower seeds, brown rice and beans. As little as two brazil nuts per day will provide you with your quota for the day.
Calcium 🦴- is needed for strong bones and teeth but it is also used in many other areas of the body, for example blood clotting and muscle contraction. Food sources include dairy products, soy, collard greens, broccoli and tofu. Plant based sources of calcium may be less bioavailable than dairy based products due to two compounds known as oxalate and phytate found within the plant. These inhibit calcium absorption within the body. So ensure you are getting ample calcium through fortified products where you can or supplement if needed. Especially true for vegan diets, or veggie diets which also exclude dairy.
Iron 🔴– plays a vital role in immune system function, transporting oxygen around our bodies through our bloodstream via our haemoglobin and contributing to normal energy levels.
Plant based foods contain a type of iron known as non-heme iron. This type of iron is less easily absorbed (bioavailable) to us compared to the iron found in animal based products known as heme-iron. This is due to the fact the non-heme iron must undergo an extra chemical conversion within our bodies to make it absorbable.
Vitamin C helps or bodies to absorb this type of iron so try to pair plant based sources of iron with a source of vitamin C when planning your meals. Plant based sources of iron include: lentils, tofu, chickpeas, beans, chia seeds, ground linseed, hemp seeds, pumpkin seeds, kale, dried apricots, dried figs, raisins and quinoa. Try to pair these with vitamin C containing foods such as broccoli and citrus fruits to boost the bioavailability of iron. Otherwise, if you are just reducing your meat consumption try to pick animal based products with higher iron levels on the days you do choose to have meat. For example: beef, chicken, canned sardines, or tuna.
Vitamin D ☀️– this vitamin is needed for the absorption of calcium into our bodies, thus contributing to the development of strong bones. Our bodies produce Vitamin D when exposed to sunlight. In the UK and Ireland during the winter months it is necessary to get Vitamin D from your diet. Foods such as fatty fish like tuna, mackerel and salmon provide vitamin D. If you are following a plant based diet which excludes fish it will be necessary to supplement with vitamin D. Speak to your doctor, dietician or nutritionist about the best supplement for your needs.
Essential Fatty Acids (Omega-3 and Omega-6) 🌻– fat is an essential macronutrient which is used by the body as an energy source and helps the body to absorb certain minerals A, D, E and K.
There are two types of essential fats that we need which the body cannot make itself. These are the Omega-3 (alpha-linoleic acid), which is linked to the prevention of diabetes and some cancers (11) and Omega-6 (linoleic acid) fatty acids.
Sources of omega-6 (LA) include: hemp seeds, sunflower seeds, walnuts and soy spread products. If you are eating a diverse range of foods whilst following a plant based diet you will be getting enough of this in your diet.
Omega-3 (ALA) on the other hand is found in high amounts in oily fish such as mackerel, salmon and tuna and may be slightly harder to obtain on an exclusively vegan or vegetarian based diet. If you are just limiting your meat intake, try to include at least one-two portions of oily fish a week in your diet to ensure you are getting enough ALA. If you are switching to an exclusively plant based diet be sure to include plenty of plant based sources of omega-3 per week, such as: chia seeds, canola oil, ground flaxseeds, walnut, soybeans and tofu.
Plant based diets promote gut health: ‘You are what you eat’
If you’ve done any research on health and well-being within the last few years you are likely to have come across the emerging evidence on gut health and its importance to our overall well-being. Our gut houses hundreds of different species of live bacteria, some good and some bad. Ever heard the phrase ‘you are what you eat’? well this is especially true when it comes to the health of your gut. The positive effects of a healthy microbiome (the culmination of all bacteria, fungi and viruses within your GI tract) go far beyond just our digestive system with more and more research showing a heathy microbiome can:
- influence your mood positively by decreasing anxiety and depression 12 through the neurotransmitter serotonin (the happy hormone)
- improve immune function (13), 70% of your immune system is directly influenced by the bacteria found in your gut and reduce the risk of chronic disease (14)
So, with the above in mind let’s look at what creates a healthy gut and how to maintain it. The type of foods we choose to eat, heavily influence the types of bacteria that will thrive with our gut, thus affecting or moods and disease prevention.
Good bacteria thrive on a type of dietary fibre (non-digestible carbohydrates), known as prebiotics, which are found only in plant based foods such as fruits, vegetables, wholegrains, nuts, and seeds. These prebiotics cannot be digested by our bodies and pass straight through the digestive tract and into the colon. Here, our good bacteria begin their work, fermenting the prebiotics and creating what’s known as short chain fatty acids (SCFA), sometimes called post-biotics. These short chain fatty acids have been studied extensively over the past few years and have been proven to have effects that stretch throughout the body. This includes regulating blood pressure (15) and may reduce the risk of developing gastrointestinal disorders, cancers and cardiovascular diseases (16). Some other studies have also made a link between SCFA and its role in preventing Alzheimer’s (17). A widely-cited study showed that vegetarians and vegans have higher amounts of beneficial bacteria bacteroides which produce these beneficial short chain fatty acids. (18)
Another highly-regarded study conducted in 2014 looked at the difference between a completely plant based diet (vegan) versus an animal based diet (macros were in line with the keto diet) today. It was shown that after only 4 days those subjects who ate a diet high in animal proteins spiked their levels or certain bacteria which have been linked to colon cancer and IBD (19) alongside a sharp drop in the short chain fatty acids which have beneficial properties, referenced.
In summary, to maintain a healthy gut microbiome it is advised to eat a wide array of plants (think colourful plate) to increase short chain fatty acids, which have been linked to lower incidences of certain cancers, type 2 diabetes and other chronic diseases.
- There is sufficient evidence to show that eating a diverse plant based diet will fulfil your bodies’ protein needs, with no need for supplementation of protein from other sources (e.g. protein shakes). If you are unsure about how much protein you should be eating or if you are concerned about whether you will need to supplement, you can refer to Dr. Hazel’s article on Protein Supplements.
- Vitamin and mineral intake need to be considered if you are switching to a purely plant based diet (vegan and vegetarians) with focus on: iron 🔴, calcium 🦴, selenium 🤒, vitamin D ☀️, vitamin B12 💊, and omega–3 and omega-6 fatty acids 🌻. Supplementation may be easier when you first make the switch until you find your feet. Consult your doctor, dietician or nutritionist if you are unsure.
- To maintain a healthy gut, studies suggest those who eat a diverse and largely plant based diet naturally ingest higher quantities of fibre which may lead to an increase in beneficial gut bacteria versus those who eat a diet high in animal protein. This beneficial bacteria works upon the fibre within our colon to produce short chain fatty acids which have been linked to a reduction in the risk of developing gastrointestinal disorders, cancers and cardiovascular diseases
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