What does it mean? Why would I be interested? How can I find a plant-based way of eating that works for me?
Plant-based eating. We are hearing a lot more about it - so what does it mean?
It can mean different things to different people. For some, it can mean eating one or two meat-free dinners a week, as part of a well-balanced diet. For others, it can mean basing all of their meals around plant foods, using animal products occasionally, but not making them the central part of the meal. There are also those who exclude certain animal-derived foods, and those who don't consume any at all. People often choose to exclude various animal products for health, ethical or environmental reasons, but as you can see there are a variety of positions you can occupy along a spectrum of plant-based eating:
semi-vegetarian/flexitarian: eat meat, poultry and seafood occasionally, most likely consuming eggs and dairy products regularly.
pescatarian: eat fish and/or shellfish, but no meat or poultry, most likely consuming eggs and dairy products regularly.
lacto-ovo vegetarian: eat dairy products and eggs but no meat, poultry or seafood.
ovo-vegetarian: eat eggs but exclude dairy products, meat, poultry and seafood.
lacto-vegetarian: eat dairy products but exclude eggs, meat, poultry and seafood.
vegan: exclude all animal products, including foods that involve animal cruelty or exploitation. This includes foods such as honey, and can also lead to the avoidance of clothing made from wool and leather.
So why are more and more people interested in going plant-based?
One of the major benefits to regularly working more plant foods into your day is to your health. In New Zealand, we're not so good at meeting our "five plus a day" target, or our fibre recommendations.
In 2008/09, when the last Adult Nutrition Survey was undertaken in New Zealand:
66.0% of the total population aged 15 years and over consumed the recommended 3 or more servings of vegetables a day, and 60.4% consumed the recommended 2 or more servings of fruit each day.
Males averaged 22.1 grams of fibre a day (recommendation is 30 grams/day), and females averaged 17.5 grams of fibre a day (recommendation is 25 grams/day).
So in short, anything that encourages us to consume more plants is a step in the right direction! In addition, eating more plant foods can reduce the amount of saturated fat, salt and added sugar we consume, by displacing some of the more processed convenience foods common in the Western diet. As you can imagine, increasing your intake of vitamins, minerals, antioxidants and fibre, while reducing your fat, salt and added sugar intake could significantly reduce your risk of developing cardiovascular disease, Type 2 diabetes and various forms of cancer.
In a 2017 review of research from 49 studies looking at the effect of a range of vegan, vegetarian and semi-vegetarian diets on the levels of certain fats in the blood (a known risk factor for cardiovascular disease), the authors found significant reductions in total cholesterol, and in LDL (so called "bad" cholesterol), compared to typical, primarily Western diets.
There is even an approach called the "Portfolio Diet", specifically designed to lower cholesterol. Its name comes from the approach it takes - it includes a portfolio of foods known to have a beneficial effect on cholesterol levels, with the intention of combining them into one diet to compound these effects. Foods in the diet include plant proteins (especially soy foods), nuts, foods rich in soluble fibre, and foods rich in (or fortified with) plant sterols. For those keen on a bit of further reading, here is a review of the Portfolio Diet in Today's Dietitian magazine, October 2018.
Vegetarian and semi-vegetarian diets can even reduce blood pressure, another risk factor for cardiovascular disease.
However, it does depend on what kind of plant foods you replace the meat with in your diets. One study I found compared two approaches: vegetarian diets that emphasised heathy plant foods (wholegrains, fruit and veg, nuts and legumes); or vegetarian diets that were high in juices or sweetened drinks, refined grains, fries and sweets. Not surprisingly, the first kind were associated with a reduction in the risk of heart disease, while the second kind were associated with an increase in the risk of heart disease. Strictly speaking there are a few highly-processed foods that are vegan (I'm looking at you, little round chocolate biscuits filled with white icing), but that doesn't mean they are healthier or should play a significant part in a plant-based diet.
As for Type 2 diabetes, vegetarian diets seem to be a powerful preventative. Various studies have examined the effect of predominantly vegetarian diets on health outcomes in a large group of Adventists in the United States. Adventists are advised by their church to avoid the consumption of meat, eggs, fish, coffee, alcohol and tobacco, and around half of all Adventists consume a lacto-ovo vegetarian diet. One study looked at the occurrence of diabetes in just under 25,700 members of the Adventist church, and found over a 21-year follow-up period that the risk of developing diabetes was approximately half that of the equivalent demographic in the general population. Another study of the same population found a 74% increase in the risk of developing diabetes when following a diet that included at least a weekly intake of meat, compared to a zero-meat diet. However, there are various nutritional and lifestyle factors at play within this population, not just the presence or absence of meat in the diet. This population does not consume alcohol, and vegetarians are known to have diets higher in legumes, wholegrain and fruit, and a higher fibre intake overall. These factors are likely to have had a significant impact on diabetes risk.
Closer to home, the BROAD study followed a small group of participants recruited from a General Practice in Gisborne, who had at least one of the following conditions: Type 2 diabetes, ischaemic heart disease (heart disease caused by narrowed arteries), hypertension (high blood pressure) or hypercholesterolaemia (high cholesterol). The intervention group followed a low-fat plant-based diet, emphasising wholegrain, legumes, vegetables and fruit. They were not restricted in the amount of food they ate, or the number of kilojoules/calories, and were instructed to eat until they were full. The results were so significant at the 6-month endpoint of the study that the researchers were ethically compelled to offer the intervention to the control group (the group who were just following their normal diet, in order to compare results with the intervention group). Two participants in the plant-based diet group no longer met the criteria for having Type 2 diabetes, they had improved their blood test results that much. The greatest drop in blood glucose was seen amongst those with the highest figures at the start of the study.
Dietary patterns rich in plant foods can also help prevent may types of cancer. There are so many beneficial compounds found in plant foods, it's hard to single out any for particular attention, but fibre, antioxidants and other phytochemical are major players. As plant-based diets increase the consumption of these beneficial compounds, it stands to reason this will translate into a reduction in cancer risk (in combination with other factors, such as not smoking, alcohol consumption within recommended limits, being sun-safe, managing stress levels, avoiding environmental pollutants, and doing some regular physical activity). Breast, prostate, colorectal and gastrointestinal cancers seem to have the greatest evidence for this preventative relationship.
So, how do you move towards a more plant-based way of eating?
The big thing is that you don't have to go vegetarian or vegan, or give up meat.
I like the approach of adding foods to your diet, rather than subtracting or eliminating any. Try adding another serve of fruit to your day. Once you've got that nailed, add another serve of veg. Then you can try bulking out some of your meat dishes with plant-based ingredients, like a tin of beans, chickpeas or lentils. This will reduce the amount of meat eaten in the meal, rather than remove it, and will add a whole lot of beneficial nutrients to your meal. If you can, have a small handful of mixed nuts a few times a week, just try and avoid the ready-salted ones. Have one day a week for a meat-free dinner, maybe another day for a fish meal. Before you know it, you will have added a whole lot of variety to your diet without feeling deprived at all!
If you decide to go full vegetarian or vegan and eliminate certain foods from your diet, there are a few nutrients you need to be aware of. Depending on what you eliminate, and what you replace those foods with, you may be at increased risk of some nutrient deficiencies:
protein
vitamin B12
vitamin D
calcium
iodine
iron
selenium
zinc
omega 3 fats
You can easily meet your nutrient needs with a well-balance vegetarian diet (variety is the key), but achieving this on a vegan diet takes more planning. In the case of vitamin B12, a supplement is recommended. If you are thinking of going vegan, or are vegan already, make sure you get your nutrition information from reliable, evidence-based sources. Websites such as The Vegan RD and Vegan Health are good resources. Here are some practical tips on meeting your nutrient needs on a vegan diet, and here you will find a British version with some extra resource links. If you are vegan and pregnant or breastfeeding, or want to raise your child vegan, ensuring the credibility of your nutrition information is even more important, to avoid irreversible effects of nutrient deficiencies on a developing foetus, or a growing infant. Such a diet will definitely require careful planning.
If you have any concerns that your current diet isn't meeting your nutrient needs (especially in the case of a vegan diet and pregnancy, breastfeeding or infant and child nutrition), it might pay to seek some personalised nutrition advice. Check out the Nutrition Society of NZ website for a list of Registered and Associate Registered Nutritionists, or the Dietitians NZ website for a Dietitian near you. Choosing to see either of these trained nutrition professionals ensures you receive the most up-to-date evidence-based advice.
Here are my top four take-home tips from today's podcast:
Add another serve of fruit to your day: think chopped fruit at breakfast, fruit for a mid-afternoon sweet snack, or fruit as a dessert.
Add another serve of veg to your day: for snacks, or in your lunch or dinner. Salad in your sandwich, fill half of your dinner plate with colourful veg; the more variety in colour the better.
Add a tin of legumes to casseroles, stews or soups: they will take on the flavour of the meat and seasonings, as well as adding nutrients and fibre, and saving money. Legumes include tinned beans (borlotti, kidney, cannellini, even baked beans), chickpeas and lentils.
Have at least one meat-free dinner a week: meatless Mondays anyone?
Just start small with one change. Once you've got used to that, chuck in another one. Remember that change takes time, and there will be changes you don't like - that's ok, ditch that one and try something else! It's not meant to be a deprivation, more of a food adventure! Just try and find ways to work in more plant foods that work for you - you may be surprised at how much of a difference it makes over time.
References:
Lanou, A.J., & Svenson, B. (2010). Reduced cancer risk in vegetarians: An analysis of recent reports. Cancer Management and Research, 3. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048091/
Madigan, M., & Karhu, E. (2018). The role of plant-based nutrition in cancer prevention. Journal of Unexplored Medical Data, 3(9). Retrieved from https://jumdjournal.net/article/view/2892
Ministry of Health. (2011). A focus on nutrition: Key findings of the 2008/09 New Zealand Adult Nutrition Survey. Retrieved from http://www.health.govt.nz/publication/focus-nutrition-key-findings-2008-09-nz-adult-nutrition-survey
Satija, A., Bupathiraju, S.N., Spiegelman, D., Chiuve, S.E., Manson, J.E., Willett, W.,...& Hu, F.B. (2017). Healthful and unhealthful plant-based diets and the risk of coronary heart disease in U.S. adults. Journal of the American College of Cardiology, 70(4). Retrieved from https://www.sciencedirect.com/science/article/pii/S0735109717375216?via%3Dihub
Snowdon, D.A., & Phillips, R.L. (1985). Does a vegetarian diet reduce the occurrence of diabetes? American Journal of Public Health, 75(5). pp. 507-512. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1646264/
Tuso, P.J., Ismail. M.H., Ha, B.P., & Bartolotto, C. (2013). Nutritional update for physicians: Plant-based diets. The Permanente Journal, 17(2). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662288/
Vang, A., Singh, P.M., Lee, J.W., Haddad, E,H., & Brinegar, C.H. (2008). Meats, processed meats, obesity, weight gain and occurrence of diabetes among adults: Findings from Adventist health studies. Annals of Nutrition and Metabolism, 52. Retrieved from https://www.researchgate.net/publication/5501979
Wright, N., Wilson, L., Smith, M., Duncan, B., & McHugh, P. (2017). The BROAD study: A randomised controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes. Nutrition and Diabetes, 7 (e256). Retrieved from https://www.nature.com/articles/nutd20173
Yokoyama, Y., Levin, S.M., & Barnard, N.D. (2017). Association between plant-based diets and plasma lipids: A systematic review and meta-analysis. Nutrition Reviews, 75(9). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5914369/
Yokoyama, Y., Tsubota, K., & Watanabe, M. (2016). Effects of vegetarian diets on blood pressure. Nutrition and Dietary Supplements, 8. Retrieved from https://www.dovepress.com/effects-of-vegetarian-diets-on-blood-pressure-peer-reviewed-fulltext-article-NDS