Kiwifruit may increase skin vitamin C and improve skin density, study finds

A small study had 24 adults eat two kiwifruit daily for eight weeks and reported higher skin vitamin C alongside increases in measured skin density and cell renewal.

Researchers tested whether vitamin C from food reaches the skin and affects skin function in a short dietary study. The trial involved adults in New Zealand and Germany who ate two kiwifruit a day for eight weeks. Measurements included blood and skin vitamin C levels and imaging and lab tests of skin structure. The work was published in the Journal of Investigative Dermatology and reported by the research team at the University of Otago. Key findings: - Twenty-four healthy adults in New Zealand and Germany took part in an eight-week intervention eating two kiwifruit daily. - Researchers measured vitamin C in blood plasma and skin, and assessed skin density and cell renewal with imaging and lab tests. - After eight weeks the study reported a substantial rise in skin vitamin C, skin density increased nearly 50%, and skin cell renewal increased about 30%. - Lead author Margreet Vissers said the skin showed a tight correlation between plasma vitamin C and skin levels and absorbed vitamin C from circulation. - A dermatologist not involved in the research, Dr. Brian Toy, noted the study was small, focused on people with low vitamin C levels, and did not show improvements in skin elasticity or protection from ultraviolet damage. - The research was partially funded by Zespri International and was published in a peer-reviewed journal. Summary: The study reported increases in skin vitamin C and measurable cellular changes after eight weeks of daily kiwifruit intake, while authors noted those changes were at a cellular level and may be difficult to detect visually. The trial was small and did not demonstrate changes in elasticity or UV protection. Undetermined at this time.