Plastic, it is literally everywhere. It lines our supermarket shelves, surrounds our ‘fresh’ food products, stores our not-so-fresh food products, lines our cookware, crockery and cups, it’s in some cosmetics and hair products, it coats receipts, can be in some teabags and even clothes. Our kids play with plastic, suck on plastic and wear plastic lined nappies from the moment they are born. In Australia our most valuable commodity is even a form of plastic…money (and credit cards for some!!)
Although plastic is now slowly filling our oceans and landfills, it had an innocent introduction to life. Prior to the invention of plastic, the only substances that could be moulded were clay (pottery) and glass, and these substances are not easily transportable. A plastic polymer made it possible to get food to soldiers at war, made food preservation easier, water transportation easier and of course, was much cheaper and always considered fine for human health because…you know, who eats plastic??
However, just like with everything that is ‘man-made’ we took something that had a legitimate purpose and used it everywhere and anywhere we could until someone realised…hang on this can’t be good for our health.
Then science agreed.
Although there are numerous components, types, forms and additives of plastic that can cause harm to human health, the two most studied plastic compounds and the effects they have on human health would have to be Bisphenol A (BPA) and phthalates (hard to say, harder to spell).
BPA is probably the most commonly heard about ‘plastic’, due to the availability of BPA-free plastic products, but very few people know what it actually is.
Not that this next bit of information means much to anyone unless you’re a die-hard plastics fan but bear with me, BPA is actually a monomeric building block of carbonate plastics, think of it like amino acids that build together to make protein, or lego blocks that connect together to make a tower, so basically loads of little BPA’s, and other monomers, join hands to create a bigger, stronger molecule. Polymerisation is the chemical process in which the little BPA monomers, and other monomers, combine together to create a large chain, or network (or lego tower!) called a polymer- the bigger and stronger molecule, making up plastic.
A 2003 estimate puts the world’s annual output of BPA at 2.2 million metric tons, and a very sizeable percentage of this comes into contact with our food and beverages.
The little BPA monomers that join hands during the polymerisation process can become unbound when exposed to elements such as heat or acidity and even just become unbound due to time; it is these unbound BPA monomers which can interfere with human health. So think reusable and washable plastic containers and drink bottles, canned food with acidic contents, such as tinned tomatoes, baby bottles, baby dummies, re-usable containers that have had acidic food stored in them, even baking paper used in the oven etc. The unbound BPA monomers leech into the food and or beverage that is storing in the plastic.
Although ingestion is considered the main source of exposure to humans, we can also get exposure via inhalation (as an estimated 100 tons of the stuff is pumped into the atmosphere by synthesis alone) and also via pharmaceutical and medical products such as catheters, certain surgical implants and many injections.
It is literally so ubiquitous it is found in umbilical cords and in human breast milk.
With the ‘BPA product industry’ a multi-billion dollar industry, it’s not a huge shock that the health implications of BPA are fiercely debated and still not fully understood.
Today, monomeric BPA is classed as an oestrogen mimic and an endocrine disrupter, but it is the levels required to cause an actual physical impact that is debated. The US Environmental Protection Agency (EPA) arrived at a value of 50mcg/kg of body weight per day as a ‘safe guide’; however since 2004 a total of 31 papers in the peer reviewed literature had reported adverse effects of BPA at doses well below the EPA suggested dose.
Adverse effects included in animal studies were:
- Increased postnatal growth in both sexes after maternal doses of 2.4mcg/kg/day
- Early onset of female sexual maturation after maternal doses of 2.4mcg/kg/day
- Altered plasma luteinising hormone levels and decreased plasma testosterone levels in males after maternal doses of 2mcg/kg/day
- Increased prostate size in male offspring following a maternal dose of 2-50mcg/kg/day
- Decreased sperm production and fertility in males following a maternal dose of 0.2mcg-20mcg/kg/day from developmental and adult exposure
- Stimulation of development of the mammary gland in female offspring at a maternal dose of 0.025mcg/kg/day
- Increased mortality of embryos following a maternal dose of 25mcg/kg/day
- Alterations in immune functions at doses of 2.5-30mcg/kg/day
- Decreases in antioxidant enzymes of adult males at doses of 0.2mcg/kg/day
- Hyperactivity at doses of 30mcg/kg/day
- Increased aggressiveness at 2-40mcg/kg/day
- Impaired learning at 100mcg/kg/day
And that’s not even all of them. Additionally, epidemiological studies have found associations between blood levels of BPA in women and impaired health including obesity, endometrial hyperplasia, recurrent miscarriages, sterility and polycystic ovarian syndrome.
It will be fantastic to write the word ‘phthalate’ over and over in this next segment (sense sarcasm), it is seriously not a great word to say or write and they are also not good for human health just like BPA.
Phthalates are incorporated into plastics as plasticisers to impart flexibility, pliability and elasticity, it is because of this reason that these guys are found in abundance in beauty products, cosmetics, perfumes, lotions, sunscreen, paints, dummies, baby bottles, kids toys, medical devices and products, food packaging and other everyday household items.
Unlike BPA, which remember get ‘bonded together’ during polymerisation and then become ‘unbound’ due to elements, phthalates are ‘free floating’ particles which make them highly susceptible to leeching and the softer and more pliable the plastic, the greater the percentage of phthalates, they can make up to 80% of the total weight of the plastic (they are found at their highest in medical tubing and IV medical bags.)
Exposure to humans occurs via medical exposure of a direct release of phthalates into the human body; inhalation from off-gassing of paint, furniture and carpet fumes; ingestion from contaminated food products and dermal uptake via beauty and care products.
There are many different types of phthalates which have been looked at to see the impact they have on human health. Phthalates are also known endocrine disruptors and have been noted to have a greater impact on male fertility than that of female fertility; they are also a suspected candidate for testicular cancer development and have also been observed to interfere with regular insulin response and the thyroid.
How to limit exposure/ support the body
Ok, so by now I’m sure you’re all thinking ‘what the…how can I get away from these things?’ well, you can’t really. They are literally E.V.E.R.Y.W.H.E.R.E what you can do though is minimise your exposure:
- use stainless steel or glass water bottles
- swap glad wrap for beeswax wraps
- buy paint-free wooden toys for your children
- use natural ‘teethers’ like frozen celery rather than a plastic teething toy
- avoid introducing a dummy
- use natural and organic sunscreen and beauty/care/cosmetic products where possible
- Replace plastic bowls and plates with bamboo ones
- Buy BPA free canned food (especially acidic things such as tomatoes)
We can also support our bodies correctly to help excrete these toxins more efficiently. After moving through phase 1 detoxification through the liver, BPA and phthalates are conjugated via the glucuronidation pathway through phase 2 liver detoxification, what this means is that after BPA and phthalates are passed through phase 1 detoxification and converted into a different, more toxic metabolite, gluconic acid is attached during phase 2 detoxification making it less toxic and enabling it to be excreted through the biliary tract and into the intestines.
Gluconic acid, the oxidation product of glucose, is mainly produced by our fungal, yeast and acetic acid microbes (which is why diversity and ‘balance’ is key to a good gut- we need these guys for some things!) Gluconic acid is a metabolite of these microbes when they digest our fibre rich foods.
Beta-glucuronidase(BG) is an enzyme found within our guts that works to ‘de-conjugate’ (or release) the gluconic acid from its attached toxic metabolite (e.g. BPA and phthalates) now, this is actually important for some things such as the recycling of certain hormones and nutrients which also move through the glucuronidation pathway which, when they are ‘de-conjugated’ can be re-absorbed through the intestines and utilised again by the body. However it is not good when it comes to the toxins and other nasties that move through that same pathway!
An overproduction of BG in the intestines can create a higher ‘re-absorption’ rate of BPA and phthalates which is where they can then go on and do most of their damage.
So how do we keep BG in check? Well our lactic acid producing bacteria, Lactobacillus and Bifidobacterium are BG inhibitors meaning they control how much is produced and in working order.
Other BG inhibitors are:
- Apple Pectin fibre (an apple a day keeps the doctor away!)
- Black pepper
- Fenugreek seeds
- Fructooligosaccharides (FOS fibres) i.e. onion, garlic, leeks, chicory, asparagus, banana
- Silymarin (milk thistle)
So to summarise, avoid using plastics where possible, use BPA and phthalate free where you can, eat a varied diet high in fibre to not only support your lactic acid bacteria but also to support the production of gluconic acid. Enjoy foods with cumin, black pepper and fenugreek. Consider supplementation of calcium-d-glucarate and milk thistle- it is important to chat with a health professional before taking these supplements as they do interfere with liver metabolism and can alter the metabolism of other medications that may be being consumed.
If you have chronic hormonal issues or have a history of any hormonal based cancers, BPA and Beta-glucuronidase can all be measured via serum and/or urine pathologies.