Oxidative damage (included UV-induced): health claims guideline.

EFSA has published a guidance to explain what are the scientific requirements for health claims referring to: antioxidant, oxidative damage and cardiovascular health.

First of all EFSA states (in accordance with Reg. 1924/2006) that the 2 main requirements to substantiate a claim are that the claimed effects have to be considered as a beneficial physiological effects and that it must be supported by adequate studies in humans.

In the first part of the document the status of ‘antioxidant’ is discussed: the concept of “antioxidant” as a benefit is rejected, but this aspect will be discussed more specifically in another post.

Regarding protection from oxidative damage, which can be claimed and is intended as proven protection of body cells and molecules (i.e. DNA, proteins and lipids) from oxidative damage, EFSA established some general requirements to substantiate these claim with reference to all the cellular structures:

–          An appropriate method of assessment should be able to determine accurately and specifically the oxidative modification of the target molecule in vivo (at least an appropriate market of oxidative modification needed).

–          A marker (method) cannot be accepted for substantiation when (technical) limitations are considered to be severe.  

 Then, as reported above, the food/constituent has to show a real beneficial effect on target molecules and it has to be demonstrated by  setting up adequate scientific studies, involving humans. Below the methods accepted to validate the beneficial physiological effect, specific for every different cellular body:

–          Proteins: the only validated method to detect oxidative damage is HPLC-MS. Proteins by products analysis (ELISA or other colorimetric methods) shows some limitation, then they cannot be considered valid alone, but just in combination with other direct methods.

–          Lipids: F2-isoprostanes in 24-h urine samples is the recommended method. LDL oxidised particles (using specific antibodies) and phosphatidylcholine hydroperoxides (using HPLC) are validated methods as well. Not allowed markers: reactive substances (TBARS), malondialdehyde (MDA), lipid peroxides, HDL-associated paraoxonases, conjugated dienes, breath hydrocarbons, auto-antibodies against LDL particles, and ex vivo LDL resistance to oxidation).

–          DNA: recommended method is the modified comet assay which allow the detection of oxidised DNA bases (e.g. use of endonuclease III to detect oxidised pyrimidines). Conventional comet assay and other methods are not suitable.

Other methods still widely used to measure antioxidant properties are to be considered worthless in the perspective of health claims. This applies to the evaluation of past studies, and future studies of benefits of food.

Armando – Sport Nutrition team

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