Joanna is a registered nutritionist and dietician with a PhD in nutritional science from the University of Sydney. She is the resident nutrition expert for Channel 9’s Today Show, contributor to magazines including Life Etc and Slimming & Health and author of numerous books including Inner Health Outer Beauty, Star Foods and the Low GI Diet.
One of the amazing things about us humans is that we can adapt and thrive on all sorts of different diets. Undoubtedly this is one of the reasons we have been so successful as a species. We have evolved since early hunter-gatherer days to eat meat and we do get many important nutrients from animal foods. But provided we are sure to include a broad range of plant foods, we can do quite nicely without them.
The decision to follow a vegetarian or vegan diet should however be based on your own personal ethics and not in the belief that your diet will necessarily be healthier. For all of us, whether or not we also eat meat, eating more plant food will almost certainly improve our health and wellbeing. But cutting out meat won’t necessarily improve it further and in many cases makes good nutrition harder. I say this not to convert you back to meat, but only to make sure you are clear on your reasons for doing so. Following a vegetarian diet is not always easy to get right and an over reliance on cheese, bread and processed grain products is common and a recipe for disaster.
On the positive side of vegetarianism is that it is arguably the most environmentally friendly diet. We can feed far more people from an area of land growing crops, than we can from the same area used to farm animals. So if you are already or would like to be a vegetarian, here are the things you need to think about.
Meat, fish, eggs and dairy products are the major sources of protein in a carnivorous diet. These foods provide protein that contains all of the essential amino acids — the building blocks of protein. While most amino acids can be made in the body, the essential group cannot and must be consumed in your diet. Most plant foods have lower levels of protein than animal foods, and they usually lack or are low in one or more of the essential amino acids. This means that in order to get the full complement of amino acids we need to be healthy you need to eat a broad range of different plant foods. For adults at least this needn’t be at the same meal as was previously thought, but so long as the day’s intake is sufficiently varied to include all amino acids this will suffice. For children, particularly young children, it is still advisable to provide the full complement of amino acids at one meal to ensure adequate protein for growth. If you continue to eat dairy foods and eggs this is a huge nutritional bonus as these foods provide all essential amino acids and can help enormously in achieving a well balanced diet. For vegans take particular care to include all the other plant protein groups every day. Soybeans and products made from them including tofu and tempeh, are particularly good additions as unusually for a plant, these foods do provide all of the essential amino acids.
Meat, especially red meat, and seafood are undeniably the best dietary sources of the most readily absorbed forms of iron and zinc. These two minerals are often low in modern diets, particularly for women, and the risk is even greater for those who don’t eat these foods. If you are prepared to eat fish and seafood this makes things easy and you can readily meet your requirements. For true vegetarians here are the best plant sources of these minerals:
|Plant sources of iron||Plant sources of zinc|
|Baked beans||Muesli||Milo™ & Ovaltine™ (fortified)||Nuts & seeds||Spinach & other greens||Wholegrains (breads, brown rice etc)||Fortified breakfast cereals (look for low GI choices)||Fortified breakfast cereals (look for low GI choices)||Hummus||Beans, chickpeas & lentils||Beans, chickpeas & lentils||Dried apricots & prunes||Dried apricots||For lacto-ovo vegetarians:||Nuts & seeds||Eggs, milk & cheese|
Bear in mind that plant foods also contain compounds such as phytates that inhibit the absorption of the minerals. You can assist your body to absorb plant iron by consuming a food or drink rich in vitamin C at the same time, and avoiding drinking tea or coffee with meals.
Long chain omega-3s have been in the research spotlight for some time and it seems more and more benefits of these essential fats are being discovered. (add link to fats page) But of course the long chain omega-3s come from fish, including the supplements, so for true vegetarians this makes it difficult to meet requirements. The best alternative is to stock up on plant omega-3s by using flaxseed oil (found in the fridge of most health or wholefood stores) and consuming walnuts and plenty of leafy greens including seaweeds. These are not quite the same but do provide some benefit by providing the precursor omega-3 fat and leaving it up to the body to make the longer chain fats. You can also help to encourage this conversion but ensuring you are not over-consuming other polyunsaturated fats such as those in common seed oils such as sunflower and soybean oils. Choose a monounsaturated fat such as olive oil for regular use.