Could Tears be Used to Effectively Measure Vitamin Deficiencies?

A new study conducted by researchers at University of Michigan and Michigan Technological University found that tears may be a viable substitute for blood samples for determining vitamin deficiencies in infants and parents.

In their study, researchers collected blood and tear samples from 15 parents and 15 4-month-old infants, who were either breastfed or bottle-fed. Concentrations of vitamins were compared between blood and tear serum levels, between infants and parents, and against self-reported dietary intakes.
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The analysis of blood and tear serum showed that water-soluble vitamins B₁, B₂, B₃ (nicotinamide), B₅, and B₉ were detected in both blood and tears, and the concentrations were similar between blood and tears for a single participant. However, infants had higher levels of water-soluble concentrations than their parents.

Likewise, fat-soluble vitamin E (α-tocopherol) was consistently detected in blood and tears, but concentrations were lower in tears than blood.

“Strong positive correlations were found between tear and blood serum concentrations of vitamin E from infants and parents and vitamin B₃ concentrations from parents, while slight positive correlations were detected for infants B₃ and parents B₁ and B₂ concentrations,” the researchers stated.

In addition, researchers found correlations in concentrations for B₁, B₂, B₃, and E in tears between parents and infants, and in concentrations of B_2, A, and E in blood serum, with stronger vitamin correlations made between breast-fed infants and their parents.

Conversely, fat-soluble vitamin A concentrations were only detected in blood serum, and in higher concentrations in parents than infants.

Their study demonstrated that tears had similar concentrations of vitamin A, B, and E as blood in infants and parents, with no significant differences observed in concentration levels between bottle-fed and breast-fed infants.

“This work is the first to demonstrate simultaneous vitamin A, B, and E detection and to quantify correlations between vitamin concentrations in tears and blood serum. Our results suggest that tears are a viable biofluid to monitor nutritional health because they sufficiently mirror blood serum data and may enhance the speed of deficiency diagnoses,” the researchers concluded.

—Melissa Weiss

Reference:

Khaksari M, Mazzoleni LR, Ruan C, Kennedy RT, and Minerick AR. Determination of water-soluble and fat-soluble vitamins in tears and blood serum of infants and parents by liquid chromatography/mass spectrometry [published online December 23, 2016]. Experimental Eye Research. doi:10.1016/j.exer.2016.12.007.