Investigating the Impact of Vitamin D Biofortified Tomatoes on Serum Levels of 25(OH)D

Overview

In the UK, vitamin D deficiency occurs frequently especially during the winter months. Vitamin D biofortified tomatoes have been developed using precision breeding technique by researchers at John Innes Centre. Biofortification uses crop breeding to increase the nutritional value of crops. The goal of the ViTaL-D study is to examine whether the vitamin D biofortified tomatoes when eaten as a soup can increase blood levels of vitamin D in men and women with vitamin D deficiency. Additionally, researchers will learn if the tomato soups are feasible and safe to eat everyday. The main questions the study aims to answer are: * Does vitamin D biofortified tomatoes increase vitamin D levels in men and women with low blood levels of vitamin D? * Is consuming vitamin D biofortified tomatoes safe and easy to eat everyday as a soup? Researchers will compare how four types of tomato soup increase blood vitamin D levels. The four types of soup are: * Soup with vitamin D biofortified tomatoes * Soup with provitamin D biofortified tomatoes * Soup with store-bought tomatoes not containing vitamin D * Soup with store-bought tomatoes with added vitamin D Participants will: * Eat one of the four types of tomato soup every day for 21 days. * Visit the clinic once every 7 days after a 12 hour fast for body measurements, tests, and surveys. * Keep a daily diary when soups are eaten and when time is spent outside.

The ViTaL-D study is a 21-day randomized, double-blind, placebo-controlled four-arm parallel pilot study conducted at the NIHR (National Institute for Health and Care Research) Norfolk Clinical Research Facility (CRF) in the Quadram Institute in Norwich. Researchers are seeking adult (at least 18 years and older) men and women who have serum 25-hydroxyvitamin D (25\[OH\]D) levels between 25-40 nmol/L to determine whether soups made with precision bred, biofortified vitamin D tomatoes will increase vitamin D levels. There are a total of 6 study visits (1 consent visit, 1 screening visit, and 4 short visits). At these visits, anthropometric measurements and vital signs will be collected. Participants will be asked to complete questionnaires (food frequency, international physical activity, and sensory evaluation). They will record their daily consumption of soup as well as their daily sun exposure and wear a UV tracker when they are outdoors. Researchers will measure fasting blood samples for serum 25\[OH\]D, serum electrolytes, calcium, phosphorous, parathyroid hormone, cholesterol, triglycerides, plasma lycopene, plasma beta carotene, and bone turnover biomarkers. Participants will be given the choice to donate optional samples of saliva and/or 24 hour urine collection. For these optional samples, researchers will quantify vitamin D metabolites (7-DHC, 1,25(OH)2D, 24,25(OH)2D, and C-3 epi 25(OH)D) in saliva and urine as well as vitamin D binding protein in saliva. Participants will consume one of four soups everyday for 21-days. The four soups are described as such: * Soup with precision bred tomatoes biofortified with provitamin D (7-dehydrocholesterol-rich, No UV-Treatment). This soup is made with precision bred tomatoes. Tomatoes have been engineered to accumulate 7-dehydrocholesterol (7-DHC, also called provitamin D, a precursor of vitamin D3). The bioefficacy of the provitamin D in the diet is largely unknown. * Soup with precision bred tomatoes (Vitamin D-rich, UV-Treated) This soup is made with the same precision bred tomatoes, but in this case, the tomatoes have been treated with ultraviolet (UV) light to convert the accumulated 7-DHC into vitamin D3. UV exposure mimics the natural process by which human skin synthesizes vitamin D3 from sunlight. * Soup with store bought tomatoes (placebo). In this soup, store bought conventional tomatoes contain negligible amounts of 7-DHC and no vitamin D3. This soup is the placebo soup. * Soup with store bought tomatoes supplemented with Vitamin D3. In this soup, same store-bought tomatoes will be supplemented with vitamin D (from lanolin).