Details

Autor(en) / Beteiligte

• Tang, Guangwen
• Qin, Jian
• Dolnikowski, Gregory G
• Russell, Robert M
• Grusak, Michael A

Titel

Spinach or carrots can supply significant amounts of vitamin A as assessed by feeding with intrinsically deuterated vegetables

Ist Teil von

• The American journal of clinical nutrition, 2005-10, Vol.82 (4), p.821-828

Ort / Verlag

Bethesda, MD: American Society for Clinical Nutrition

Erscheinungsjahr

2005

Quelle

Oxford Journals 2020 Medicine

Beschreibungen/Notizen

• BACKGROUND: The vitamin A value of spinach and carrots needs to be measured directly. OBJECTIVE: The objective was to determine the vitamin A value of intrinsically labeled dietary spinach and carrots in humans. DESIGN: Spinach and carrots were intrinsically labeled by growing these plants in 25 atom% ²H₂O nutrient solution. Growth in this medium yielded a range of trans {szligbeta}-carotene (t{szligbeta}-carotene) isotopomers with a peak enrichment at molecular mass plus 10 mass units. Seven men with a mean (±SD) age of 59.0 ± 6.3 y and a body mass index (in kg/m²) of 25.7 ± 1.5 consumed puréed spinach (300 g, 20.8 [micro]mol t{szligbeta}-carotene equivalents) or carrots (100 g, 19.2 [micro]mol t{szligbeta}-carotene equivalents) with a standardized liquid diet (no extra fiber) in random order 4 mo apart. Seven women with a mean (±SD) age of 55.5 ± 6.3 y and a body mass index of 26.4 ± 4.2 consumed puréed spinach only (300 g, 20.0 [micro]mol t{szligbeta}-carotene equivalents). A reference dose of [¹³C₈]retinyl acetate (8.9 [micro]mol) in oil was given to each subject 1 wk after each vegetable dose. Blood samples were collected over 35 d. RESULTS: Areas under the curve for total labeled serum {szligbeta}-carotene responses were 42.4 ± 8.5 nmol · d per [micro]mol spinach {szligbeta}-carotene and 119.8 ± 23.0 nmol · d per [micro]mol carrot {szligbeta}-carotene (P < 0.01). Compared with the [¹³C₈]retinyl acetate reference dose, spinach t{szligbeta}-carotene conversion to retinol was 20.9 ± 9.0 to 1 (range: 10.0-46.5 to 1) and carrot t{szligbeta}-carotene conversion to retinol was 14.8 ± 6.5 to 1 (range: 7.7-24.5 to 1) by weight. CONCLUSIONS: Spinach and carrots can provide a significant amount of vitamin A even though the amount is not as great as previously proposed. Food matrices greatly affect the bioavailability of plant carotenoids, their efficiency of conversion to vitamin A, or both.