My teenager wants to become vegetarian, how do i ensure she gets all the nutritients she needs?

According to the American Dietetic Association's position paper on vegetarian diets, well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.
 
As does any person on a vegetarian (or any other diet, for that matter), a teenager should take responsibility for their health by ensuring they include a wide variety of nutritious foods in their diet, including fresh fruits and vegetables (including leafy greens), legumes, whole grains and nuts and seeds. They should also ensure an adequate intake of nutrients like vitamin B12, iron, essential fatty acids and iodine.

Great question! A well planned vegetarian diet can still be nutritionally adequate. The important nutrients to ensure she is getting whilst adhering to a vegetarian diet include protein and iron.

Good source of protein for vegetarians include Sanitarium nutmeat/ TVP (textured vegetable protein), Quorn products, soy burgers or tofu. These high protein alternatives can be used in place of red meat, mince, chicken or fish. Healthy high protein snacks to include are nuts, nut spreads such as peanut butter, tahini and hummus. Vegetarian sources of iron include wholegrains breads and cereals, green leafy vegetables, milo and lentils. Try and get your daughter to eat a vitamin C rich foods when eating these non meat sources of iron. For example, eat berries with wholegrain cereal or capsicum with broccoli. Vitamin C boosts iron absorption.

With adolescents, it is also really important to ensure they are meeting their calcium requirements through 3 serves of low fat dairy each day. 1 serve = 250ml low fat milk (cows milk or calcium enriched soy milk), 2 slices/40g reduced fat cheese or 200g low fat yoghurt (cows or soy yoghurt).

It may also help the transition if the whole family eats at least 1 vegetarian meal per week, so your daughter doesn't feel excluded. A spaghetti bowl made with Quorn mince instead of regular beef mince may even go undetected by the rest of the family! Happy cooking!

I believe there is absolutely no danger at all with a teenager switching to a vegetarian, or in fact, vegan diet. I think a great rule of thumb is that if a person is eating a variety of predominantly whole foods, and they are getting enough volume (which can be monitored by body weight changes), then they will get adequate nutrition. Iron and Protein ahve been made into issues over the past 40 years with no genuine foundation. Human Breast Milk, for example is only 5% protein by calories. This is a very low protein level compared to the milks of other animals. Humans do not have a high protein requirement. When working as an AFL Conditioning Coach and Nutritionist, I had my best success in adding lean muscle to teenage boys by supplementing their diest with Avocados, Nut Butters and Olive Oil. These foods filled the energy gap, allowing the protein they did use for the anabolic processes in muscle recovery. These boys grew bigger and stronger without increasing body fat.

Remember, the mountain gorilla has the closest physiology to a human and they live well on bamboo. But, they do eat huge quantities.

JTx

As mentioned, a well-balanced vegetarian diet is not difficult to manage. I won't repeat what others have said and just make a few points.

1. Quorn is a great product (freezer section in supermarkets), the family really may not notice it in a Bolognese sauce, especially if you don't say anything…

2. Frittatas (eggs and vegetables) make great dishes to enjoy hot or cold and good for lunches.

3. Encourage her to eat legumes or lentils at least 3-4 times per week (min 1/2 cup per serve). Add 3-4 bean mix to salads, frittatas and pasta sauces. Experiment with Dahl (easy to make), your daughter can have 3/4 cup Dahl with her rice/potatoes and veggies while the rest of the family has meat/fish with their rice/potatoes and veggies.

4. Add nuts (30g per serve) and seeds (1 tbls) to salads and stir-fries - delicious! 

5. Be patient. You may find she decides to start eating meat (or fish) again down the track. Not supporting her may just make her more determined, as I'm sure you're aware!

You may even find you enjoy having a meat free meal once/twice per week, a good idea for everyone!

I have seen this response many times when teenagers visit the abattoir.  It depends how drastic she wants to become. Many teenagers will still eat fish and eggs which makes ensuring she gets all her nutrients much easier. Different people follow different forms of vegetarianism. A true vegetarian eats no meat at all, including chicken and fish. A lacto-ovo vegetarian eats dairy products and eggs, but excludes meat, fish, and poultry. It follows, then, that a lacto vegetarian eats dairy products but not eggs, whereas an ovo vegetarian eats eggs but not dairy products. Teens need to be sure their diets include enough nutrients to fuel growth, particularly protein and calcium. She can help you design meal plans that include adequate vitamins and minerals. Getting enough protein isn't tough with a well-planned vegetarian diet, especially if you include eggs and dairy. It's when a vegetarian diet isn't planned at all that nutrition trouble can start. All too often people give up eating meat but end up eating more carbohydrates and snacks. Look for alternative sources of protein, including beans (kidney beans, chickpeas, and lentils, etc.), nuts, soy, and low-fat dairy products. If you're a vegan, you can still get protein from eating beans and soy products, but it may be a little harder to get enough, and you also have to pay attention to other important nutrients like B vitamins, iron, zinc and calcium. If you're on a restrictive diet or are concerned about any aspect of your nutrition, set up an appointment with an accredited  dietitian.