As a group, the B vitamins are especially important for maintaining a positive outlook on life. Deficits of various B vitamins can lead to anxiety, irritability, nervousness, depression and personality changes. A deficiency of vitamin B3, in fact, leads to pellagra, a disease that used to be common in the southern regions of this country. Pellagra’s signs and symptoms include the “4 Ds”: diarrhea, dermatitis, dementia and, in many cases, death.
As we learned earlier, there are strong physical and biochemical links between your mind and body. Your thoughts have a profound influence on the health of your immune system and on other parts of your body. Happy, positive thoughts promote a strong immune system and good health. Negative, unhappy thoughts actually depress the immune system and encourage disease.
So the B vitamins, by helping to keep you happy and positive, have a benefical effect on your immune system. A deficiency of B vitamins, which leads to unhappiness and personality changes, harms your immune system.