Coenzyme Q ₁₀ (CoQ ₁₀ ) is an essential compound that is involved in energy production and is a lipid-soluble antioxidant. Although it has been proposed as an antiaging and a health-supporting supplement, its low bioavailability remains a significant issue. Concurrent food intake enhances the absorption of orally administered CoQ ₁₀ , but it has not been fully established whether specific food substances affect intestinal CoQ ₁₀ absorption. Therefore, to determine whether the bioavailability of supplemental CoQ ₁₀ is affected by diet, P30, a granulated and reduced form of CoQ ₁₀ , was dispersed in four different foods, clear soup, miso soup, milk soup, and raw egg sauce. Those foods which contained CoQ ₁₀ were consumed on different occasions at intervals of 6–14 weeks by the same participants. Thirteen participants were recruited in the single-dose and repeated clinical study. When miso soup containing P30 was provided, the serum CoQ ₁₀ concentration increased faster than when participants consumed other P30-containing soups or a P30-containing raw egg sauce. The area under the curve for serum CoQ ₁₀ during the first 5 h after consumption of the P30-containing miso soup was approximately 1.5 times larger than those after the consumption of other P30-containing meals. These data imply that the absorption of CoQ ₁₀ supplements can be enhanced by consuming them with food and in particular with specific food substances, such as miso soup.