The recommended daily allowance for vitamin B3 for healthy male's age 19 to 30 years old is 16 milligrams a day. For females, it's 14 milligrams per day. Vitamin B3, also known as niacin, has many benefits. It's great for digestion. It helps with energy. It helps lower cholesterol. And it really is great for your mental health and brain functioning. Also, if you're diabetic, it's important to know that vitamin B3 is helpful in treating diabetes and regulating high blood sugar levels. A few good, natural sources of vitamin B3 are liver, organic chicken and beef, dark leafy green vegetables, and tomatoes. If you're finding it difficult to get your vitamin B3 from natural food sources, definitely look into the possibility of taking vitamin B3 supplements.