People who do not consume animal products (meat and fish) are broadly defined as vegetarians. Vegetarianism has its benefits and its drawbacks in relation to keeping a balanced diet.
However to enter in details, different classes of vegetarians exist:
- Lacto vegetarians: people who consume dairy products but not eggs.
- Ovo vegetarians: people who consume eggs but not dairy products.
- Ovo-lacto vegetarians: people who consume both eggs and dairy products (this is the most common type of vegetarian diet)
- Vegans: people who do not consume any animal products.
Animal based products provide important nutrients that are sometimes scarce or absent in plant based foods. For this reason vegetarians have to pay attention to their diet and assure they have a correct intake of all the essential nutrients needed by the human body.
Focus on Macronutrient intake!
Vegetarian VS Omnivores
- The protein intake of vegetarians is often lower in comparison to that of omnivores. However the amount of proteins ingested is often sufficient to maintain a correct nitrogen balance.
- The intake of carbohydrates is usually higher in vegetarians in comparison to the omnivores. Therefore their fibre intake is higher with all the associated health benefits.
- The proportion of calories derived from fat is similar between omnivores and vegetarians.
Usually the vegetarian intake of polyunsaturated fatty acids is higher than that of the omnivores.
PROTEINS: It is very important for vegetarians to consume a very broad range of plant based products to have the correct intake (and the correct variety) of proteins. Good sources of proteins are:
- Nuts and seeds
- Soya products
- Eggs (when applicable)
- Dairy(when applicable)
Pay attention to the limiting amount of amino acids. Some plants lack of important amino acids (AA) as:
- Wheat: lysine
- Rice: lysine and threonine
- Corn: lysine and tryptophan
- Beans: methionine
- Chickpeas: methionine
In a meal, try to select and consume those products with different limiting amino acids to do not miss important AA.
CARBOHYDRATES: It is very important to eat good quantities of carbohydrates that can be found in potatoes, pasta, rice, bread etc. The CHO intake should be approximately 1/3 of the total food eaten daily.
OMEGA 3: Omega three are essential fatty acids that can be consumed only within the diet. They are important for cardiovascular health, alongside eye and brain development. It is important for vegetarians to eat good sources of alpha linoleic acids such as flaxseed, walnuts, canola oil and soya.
There are some micro nutrients that are absent or scarce in plant food products and for which a particular focus is worth such as:
- Vitamin B12
- Vitamin D
Even if the iron present in animal produce is more bio available than the iron found in plant based products , good additional sources of iron for vegetarians are:
- Dark green vegetables
- Fortified cereals
Vitamin C enhances the absorption of iron, while tea and phytate can negatively influence iron absorption.
Vegetarians who do not eat both eggs and dairy products need to ensure they have the correct intake of this vitamin. Vitamin B12 deficiency in fact can cause elevated plasma homocysteine levels and increase the risk of neurological disorders. Furthermore a high intake of folate in conjunction with a low intake of Vitamin B12 is very dangerous. In fact the high level of folate can mask the symptoms of Vitamin B12 deficiency causing a serious health risk.
Foods with good amounts of this vitamin include:
Vegans and ovo vegetarians can have problems meeting their requirement for these nutrients due to the lack of dairy products in their diet. Furthermore some plant based products such as legumes can alter and modify the absorption of calcium due to phytate.
Good sources of calcium are:
- Dairy products (when applicable)
- Fortified soya, bread
- Green leafy vegetables
- Dried fruits
Which life stages worth particular attention when following a vegetarian diet?
People undertaking a vegetarian diet during these particular frail life stages are recommended to carefully plan their diet making sure they have the correct intake of micro and macronutrients. The help of a dietician could be very useful.
Some health benefits resulting from vegetarian diets
In comparison to omnivores vegetarian have, on average:
- A lower serum cholesterol level (approximately 20%).
- Lower blood pressure, this is probably caused by a high intake of potassium through fruits and vegetables
- A lower rate of hypertension
- A lower rate of type 2 diabetes
- A lower incidence of ischemic heart disease
- A lower BMI in comparison to omnivores. However, vegetarians over 60 have a higher difficulty maintaining muscle mass
- Escott-Stump, S. (2015). Nutrition and diagnosis-related care. Wolters Kluwer.
- Foster M., Samman S., Vegetarian diet across the life cycle: impact on zinc intake and status. Article in press.
- Geissler, C., & Powers, H. (2010). Human nutrition. Elsevier Health Sciences.
- Webster-Gandy, J., Madden, A., & Holdsworth, M. (Eds.). (2011). Oxford handbook of nutrition and dietetics. OUP Oxford.