When using the RDA as a guide for vitamin and mineral intake, the combined amount of those found in food and in supplements is used to determine the correct intake.

Yes, when using the RDA as a guide for vitamin and mineral intake, the combined amount present in the food and supplements must be counted to determine the correct intake.

Explanation:

Both vitamins and minerals are micronutrients and are required by the body in limited amounts.

The RDA (recommended dietary allowance) should be based on the upper intake level which is the highest tolerable level of nutrient intake by an individual daily in the form of food, supplements, and water which will not lead to any adverse effects.

If the nutrient content in supplements is neglected, then the daily intake might exceed RDA and UL leading to conditions like hypervitaminosis.