Final answer:
Excessive intake of niacin can cause symptoms like peptic ulcers, hyperglycemia, and gout, while too much vitamin B6 can lead to nerve damage. Both these vitamins have established tolerable upper limits, and it is essential not to exceed them to avoid adverse health effects.
Step-by-step explanation:
Effects of Excessive Niacin and Vitamin B6 Intake
Consuming niacin and vitamin B6 beyond their tolerable upper limits (UL) can lead to a range of adverse health effects. For niacin, excessive intake can cause symptoms such as peptic ulcers, hyperglycemia, dizziness, and gout. These symptoms are alarming as they indicate the onset of toxic reactions in the body. Similarly, an overdose of vitamin B6 can result in nerve damage (neuropathy), which might manifest as sensory changes or loss of control over bodily movements. In general, while both these vitamins are essential micronutrients, overdosing on them can be detrimental, underscoring the importance of adhering to their respective tolerable upper intake levels.
Although deficiency diseases caused by a lack of niacin or vitamin B6, such as pellagra or various neurological and dermatological issues, are significant health concerns, the inverse - overconsumption of these vitamins through supplements or fortified foods - should also be carefully avoided to prevent toxicity.