BORIC ACID TOXICITY What is Boric Acid? Boric acid or borax has been proven to cause adverse health effects in human as it causes cell toxicity when consumed in excess. This toxicant is water soluble, colourless compound with a salt like white powdered appearance (See, 2010). It’s commonly used as a pesticide and herbicide in agriculture since 1948. This toxicant is also used in the medical industry to make antiseptics that are potent to eliminate bacteria and fungi (Yiu et al., 2008). Unfortunately, boric acid has crept slowly into our food chain disguised as a food preservative most often used in staples particularly yellow noodles. The illegal use of this food preservative by local food producers is to enhance the taste, texture, and colour and as a way to control the gelatinization process of the noodles (Yiu et al., 2008). In 1988, the potential threat of this toxicant was seen during the Chinese Festival of the Nine-Emperor Gods with 13 reported deaths (Chao, Maxwell and Wong, 1991). Hence, the Ministry of Health Malaysia have disapproved and banned the use of Boric acid as a food preservative ever since the declaration by FAO/WHO Expert committee of its cumulative and unsafe nature.
33%
20%
17%
30%
Yellow Noodle
Fish Ball
Wantan Noodle
Other Noodles
Percentage of Boric Acid (µg g-1) in food samples
How much is toxic?
LD50 value High ≤ 50
mg/kg
Low
>500-5000
mg/kg
Trend
03
05
04
Use of boric acid was banned in the country and those who flout this law can be fined/jailed.
Negri Sembilan recorded the highest percentage of boric acid misuse, followed by other states. (Malaysian Medical News, 2006)
Ex-Minister Datuk Dr Chua Soi Lek stated that spring roll & various types of noodles contain boric acid
MECHANISM OF BORIC ACID TOXICITY
on Health
H3BO3 A
Easily absorbed into the body cells through ruptured mucous membranes (Hamilton and Wolf, 2007; Murray, 1998). Studies reported that the acid is entirely and quickly absorbed when ingested (Moore, 1997).
Water soluble characteristics of boric acid made it easily distributed in body tissues such as liver, kidney and brain (Murray, 1998; Moore, 1997) through passive diffusion.
Efect
D
Ingestion of large amount of boric acid over a short period of time can affect the gastrointestinal organs, digestive system, brain but death has been attributed to respiratory failure (Toxicological Profile for Boron, 2014). Testicular lesions and impaired fertility have been observed in experimental animals (Cfs.gov.hk, 2014). It is classified as a group E carcinogen by the US EPA.
Sx of
Toxicity Vomiting
M
Borax is biotransformed to boric acid, an inorganic acid (Baselt, 2004) however not metabolized beyond the boric acid structure because high energy is needed to break the boron-oxygen bond.
Dysentery
Dermatitis Renal Failure & Damage to the blood vessels (Malaysian Medical News, 2006)
Eliminated largely unchanged, through urinary system via glomerular filtration as in animals and humans (See, 2010).
E
Pre of
Toxic Sx Consumption of cooked, raw or juiced radishes can improve liver’s detoxification process.
Advice for Public • Obtain food from reliable sources. • Maintain a balanced diet. (Janny, 2009)
Main References
1.Baselt, R.C., 2004. Disposition of Toxic Drugs and Chemicals in Man. 7th Edn., Biomedical Publications, Foster City, ISBN: 0-9626523-6-9, pp: 1254. 2.Moore, J.A., 1997. An assessment of boric acid and borax using the IEHR evaluative process for assessing human developmental and reproductive toxicity of agents. Reprod. Toxicol., 11: 123-160. DOI: 10.1016/S0890-6238(96)00204-3 3.Yiu, P., See, J., Rajan, A. and Bong, C. (2008). Boric Acid Levels in Fresh Noodles and Fish Ball. American Journal of Agricultural and Biological Sciences, 3(2), pp.476-481.
Isothiocyanates naturally found in radishes acts as an anti-cancer agent preventing the carcinogenic properties of boric acid. (Chia, 2006)