There has been a big move in medicine and medical literature looking at the role of ‘full time’ plant based diets or ‘part time’ plant based diets. Many of the studies conducted on plant based diets have been done in the Western world, so it’s important to keep in mind that they may not be applicable to all nations and ethnic backgrounds.
So what is a plant based diet: in essence it is a diet focussed on consumption of nutrient dense plant foods (vegetables, beans, lentils, nuts, the list is long). Importantly, studies show that plant based diets can help treat obesity, diabetes, heart disease, high blood pressure and improve long term health.
If you are interested in plant based diets, and especially if you are a vegetarian or a vegan, you will have heard questions about whether you can get everything your body needs from plants alone. We ask the same questions in medical world. There are concerns by both patients and doctors alike whether plant based diets are too ‘restrictive’ and whether patients can get adequate amounts of key nutrients.
Here’s what’s important:
Below is a brief review of the nutrients we need and how we can get them from a plant based diet.
Essential amino acids – these are proteins that cannot be made by the human body. Whilst they may not exist in many plant based sources they can be received from simple combinations of plant based foods – examples being brown rice with beans, hummus with whole wheat pitta.
Iron
plant based diets certainly contain iron – usually in foods such as beans, spinach, oatmeal and tomato juice. Iron in plants has lower bioavailability than in meat and some doctors are concerned that total iron levels are lower in people who follow a strict plant based diet. That may be relevant for people with conditions in which they need ‘full’ iron stores such as heavy menstrual periods, pregnancy and anaemia.
Calcium and Vitamin D
Calcium can be obtained from plant based sources and not only from dairy products as is often the misconception. Calcium is found in foods such as mustard greens, bok choy and kale. Other foods are also rich in calcium (such as spinach) but undergo a process called oxolation and so are poorly absorbed. Calcium is key to bone strength and density.
Most Vitamin D is derived from sunlight (approximately 90%) while dietary sources include fortified cereals and soy milk. In light of the sun being the primary source of Vitamin D, diet plays a smaller role in ensuring Vitamin D levels are optimal.
Healthy fats
Omega 3 and Omega 6 are the essential fats. Vegans are most likely to be deficient in Omega 3 which is found in oils fish such as salmon, mackerel and sardines. However, plant based sources include flax seeds and walnuts. Omega 3 has been shown to protect against both heart disease and stroke.
Here’s what’s ALSO important:
You can get most of the nutrition you need from plants. But ultimately the optimal diet will vary for each of us, and you have to find the right fit for you, based on your lifestyle, and your body.
My advice:
Most people would benefit from integrating a more plant based approach to their nutrition. It often leads to improved understanding of the nutritional content of different types of food sources and with that often come improved habits. You don’t have to go all the way, start with one or two vegetarian days a week and if you have any concerns discuss them with a registered dietician or a doctor with an interest in nutrition.