Zinc bound in yeast promotes superior bioavailability

Tag : gluconate salt
One of the studies demonstrated that zinc-enriched yeast was 3.7 times more bioavailable - absorbed and found in greaterconcentration in the liver - than the zinc gluconate, report the scientists.

Zinc, one of the most plentiful trace elements in the body, secondonly to iron, mediates many physiological functions.

It is believed to be essential for maintaining a healthy immunesystem; recent science suggests the mineral could also influencememory, muscle strength and endurance in adults. Zinc nutrition invery young children has been related to motor, cognitive andpsychosocial function.

"Little was known about the relative bioavailability of thedifferent sources of zinc, and how this may impact the clinicaloutcome," said Dr Thomas Tompkins, Microbiology and Biochemistry director forInstitut Rosell/Lallemand, and co-investigator in both studies.

"[Our] comparative study has demonstrated the clinical relevance ofthe form of zinc supplement in the relative bioavailability of themineral," he added.

Today's mineral supplement market offers a swathe of differentforms, among these mineral-enriched gluconates and yeast areconsidered two of the more biologically available supplements.

For the first study, results for which were published last year,the objective was to demonstrate whether zinc was absorbed betterby healthy male volunteers when given supplements where the mineralis found organically bound in yeast (using Lallemand's zinc yeastproduct Lalmin Zn) or as a salt gluconate form.

The trial used a randomised, two-way crossover design. Urine,blood, and faecal samples were collected and analyzed over a 48hour period after a single dose of supplement. The net zinc balanceand the relative bioavailability were calculated.

While no differences were observed in urine excretion of the twosupplements, zinc gluconate gave higher zinc concentrations in theblood in the first six hours but also showed greater losses in thefaeces.

" Zinc yeast also increased in blood with time but showedsignificantly less loss in the faeces ," the scientists report.

Thus, the net zinc balance after 48 hours for zinc yeast was 9.46,and for the gluconate it was -2.00, indicating that Zn gluconatesupplementation contributed to a net loss of zinc, they added.

The purpose of the second study - that also used Lallemand's LalminZn product - was to use zinc or copper deficient rats to determinewhether the organically bound mineral in yeast or the saltgluconate form was more bioavailable.

The scientists write that "it was demonstrated that zinc-enriched yeast was 3.7 times morebioavailable than the zinc gluconate and that copper-enriched yeastwas 1.4 times more bioavailable than the Cu gluconate."

The recent Vitafoods trade show highlighted a drop in ingredientinnovation, suggesting that the waiting game on approval may bestifling innovation across the board.

While the zinc yeast product from Lallemand Health Ingredients (LHI) has been on the European market for several years, theCopenhagen-based firm is, like its competitors, awaiting approvalfor the positive list from Europe's risk assessor, the EuropeanFood Safety Authority. For the industry, the lack of an EFSAdecision is still a clear barrier to trade.

"This is a problem for us and our competitors. No customer is goingto go ahead with formulation until approval is met," Julie Rosenborg, area sales manager at LHI tellsNutraIngredients.com. Indeed a sentiment shared across theindustry.

LHI is expecting approval from EFSA for the mineral enriched yeastsupplement within the year, with ongoing research and developmentinto a brand that "has a key selling point, the superior bioavailability of ouryeast," added Rosenborg.