Nutrition – micronutrients, additions and hydration

Nutrition information

Black coffee (medium strength) contains no significant amounts of the macronutrients, fat, carbohydrate and protein and therefore contains only 1-2 kcal per 100ml^2,6,15.

However, the final nutritional profile of a cup of coffee will be affected by several factors:

• The addition of milk, cream, sugar or other sweeteners to taste will affect the final nutritional value and may increase the calorie content
• The variation in cup sizes used may also alter the nutritional value

Black coffee contains a number of micronutrients, notably potassium, magnesium and niacin. The sodium level is very low. The data below provides the micronutrient nutritional profile of 100ml of medium strength black coffee¹⁵.

A review estimated that one portion of coffee brew could provide 7.5% of the daily magnesium requirement for women and 6.4% for men, as well as 6.6% of the daily potassium requirement. Coffee also provides small amounts of phosphorus and sodium (up to 2.2% of daily requirements) and calcium (up to 0.7% for women and 0.6% for men). The authors concluded that consuming three to four cups of coffee per day could make a valuable contribution to magnesium intake, particularly given the risk of magnesium deficiency in modern societies¹⁶.

The type of water used in preparation (i.e. hard or soft water) may also influence the micronutrient content of a cup of black coffee, particularly in relation to calcium and magnesium levels. Slight variations in composition may occur due to origin, growing conditions, blend composition and processing of the coffee.

Coffee and hydration

Black coffee contains in excess of 95% water and, according to research, when consumed in moderation, contributes to fluid levels and does not lead to dehydration. Therefore, a cup of coffee can help contribute to the daily fluid balance^4,17.

Studies have shown that caffeine consumption, up to the equivalent amount found in 5 cups of caffeinated coffee, does not cause dehydration^4,17. There may be a mild short-term diuretic effect from caffeine but this is not strong enough to outweigh the benefits of fluid intake from coffee consumption⁴.

Research suggests that moderate caffeine consumption does not alter total body water and fluid distribution¹⁸ and drinking a variety of caffeinated beverages, such as coffee, can contribute to meeting the body’s requirement for fluid⁴. The available evidence does not support the need to avoid moderate coffee consumption in order to maintain fluid balance.