If you're a strict vegetarian or vegan, you want to make sure you're getting enough vitamin B12. The reason why this is necessary is that vitamin B12 comes mainly from animal food sources including fish, meat, eggs, and dairy products.
If as strict vegetarian or vegan you are experiencing symptoms like low energy, brittle nails, brittle hair, depression, or chronic fatigue these might be signs of a vitamin B12 deficiency. So, you want to make sure you get your vitamin B12 serum levels checked regularly and you may need to take a vitamin B12 supplement.
The cheapest way to get our B12 is probably one 2,500 micrograms sublingual chewable or liquid supplement of Cyanocobalamin once a week. This stuff is dirt cheap. You can find a 20-year supply online for about 40 bucks. All the B12 our body needs for $2 a year. Of course, the stuff doesn't last 20 years. There's a four-year expiration date so share it with some friends.
Another important vitamin for strict vegetarians or vegans is vitamin D. The only food sources you can get vitamin D from are fatty fish, cod liver oil, and eggs. So, for strict vegetarians and vegans, taking a vitamin D supplement can be a really good idea, also.