So Sodium Benzoate is going to kill us but Benzoic Acid is ok……….
So Sodium Benzoate is produced by reacting Benzoic Acid with Sodium Hydroxide to form the Sodium SALT of the Benzoic Acid. It makes no sense for the Natural News article (September 2011) to claim that Benzoic Acid is OK as it appears in fruits in low levels but Sodium Benzoate is bad because it is man made because when used in a formulation Sodium Benzoate actually becomes Benzoic Acid and Sodium Salt.
So either Benzoic Acid is bad in this situation or it isn’t.
Here is my advice to customers who have brands and are confused about whether Sodium Benzoate is right for them:
If Benzoic Acid is bad then there would need to be a health warning on fruits and vegetables, especially berries and apples (which naturally contain around 0.05-0.1% of this).
It is true that the ingredient is man made rather than being extracted from fruit but with such a simple chemical as this there really would be no difference in risk factor or biological activity.
With regards to its potential as a carcinogen that is unlikely given its GRAS status (generally regarded as safe). There were no adverse effects found in humans at doses of 647-825 mg/kg per day when trialled.
If a person were to use 100g of moisturiser per day they would be exposed to a maximum of 0.5g in total all over their body.
If they weighed 50Kg this would equate to an exposure of 10mg/ per Kg.
If the person weighted 100Kg the exposure would be 5mg/ per Kg.
The average apple weighs 150g and 0.05% of this is Sodium Benzoate giving an exposure of 0.075g so they would need to eat the equivalent of 6.6 apples to get the same exposure to Benzoic Acid per day via that fruit. However, given that when we eat a product everything gets into the body vs a hugely variable (and usually much lower) percentage of ingredient passes into the body through the skin there is a very good chance that just eating 1-3 portions of fruit a day would put you at higher exposure level to Benzoate than the cosmetic.
It is very difficult to avoid the use of preservatives in cosmetics because cosmetics are just so nutritious for microbes. I generally suggest to customers that are wondering about preservatives to try leaving a yoghurt or milk based product out on the kitchen table for a few days and see what happens. Mould generally grows after 2-5 days depending on the environment, bacteria is less easy to spot but is still there. It only takes 48 hours of being un-protected for a cosmetic to become unsuitable to use in terms of micro. We expect our cosmetics to last for months if not years (2.5 years is the recommended shelf life for a cosmetic).
Clients don’t have to use benzoates and it isn’t as if they are without their risks. Benzoates can be irritating to the skin because of their microbial activity and can make a product feel tingly if there is no oil phase. That said they have been used safely for many years and are a low-cost broad-spectrum option available to the Organics market. There are guidelines of how much we can use in a product to avoid irritation and we do stick to that.