Synthetic V Natural Vitamins: 4 Reasons To Go Natural

Synthetic V Natural Vitamins: 4 Reasons To Go Natural

Synthetic Vitamins 

Synthetic vitamins are those which are derived from artificial sources like petroleum, coal tar, chemicals, GMOs and other raw materials. They are typically man made and are used in almost every traditional supplement you will find on the market. Unless otherwise mentioned on the label, assume that your vitamins contain synthetic forms of vitamins and minerals.

Naturally Occurring Vitamins

Natural vitamins are those which are found naturally in wholefoods. They are not derived from chemicals or other materials but naturally occur within the environment. For example, beef liver naturally contains bio-available amounts of b12, vitamin A, folate and riboflavin to name a few. Likewise, camu camu is a concentrated form of natural vitamin C. Wholefood sources of vitamins and minerals also come with a number of other cofactors, nutrients, peptides and enzymes which help with bioavailability, meaning that these nutrients are better recognised by the body in comparison to isolated and synthetic forms.

1. Synthetic Vitamins Are Derived From Toxic Sources

Many people may think that their vitamins are sourced from food sources but this is not true. Close to 100% of common vitamin supplements on the market are derived from synthetic sources and go through heavy processing to produce the finalised vitamin. This may include the use of known toxins and solvents. For example, the majority of B vitamins are usually derived from coal tar derivatives and are mixed, fermented or enacted with other chemicals and compounds to create the desired end product. Below is a list of the most common vitamins, the natural whole-food source of the vitamin and how it may be made synthetically.

Vitamin A (Retinol or Beta Carotene)

Natural Retinol or Retinyl esters in preformed form (most bioavailable) is found in good amounts in beef liver, cod liver, eggs and fish. Beta carotene which is a precursor to vitamin A is found in good amounts in carrots, pumpkin and darky leafy vegetables. Synthetic Vitamin A (most commonly reinyl acetate) is usually a vinyl or coal tar at one stage during processing. Otherwise, beta carotene is commonly extracted from seed oils like palm or from benzene extracted from coal tars.

Vitamin B1 (Thiamine) 

Also known as thiamine, natural vitamin B1 is commonly found in beef liver, fish and leafy vegetables and rice. The synthetic form of B1 (thiamine hydrochloride or thiamine mononitrate) is made from hydrochloric acid, acetone, ammonia, and grewe diamine (a coal tar derivative).

Vitamin B2 (Riboflavin)

Natural riboflavin is found in good amounts in beef liver, eggs, salmon and organ meats. Synthetic B2 comes in an orange powder and is made with acetic acid, nitrogen and can be fermented via genetically modified organisms.

Vitamin B3 (Niacin)

Natural niacin is found in high amounts in beef liver, muscle meat (beef), fish, brown rice, avocados and nuts and seeds. Synthetic niacin is typically made in a process involving formaldehyde and ammonia

Vitamin ‘B5’ (Pantothenate)

Natural Pantothenate can be found in high amounts in beef liver, shittake mushrooms, salmon, eggs, broccoli and nuts and seeds. Synthetic forms of Pantothenate which comes in the form of panthenol or pathothenic acids involve either the use of alcohol or involve the use of formaldehyde.

Vitamin B6 (Pyridoxine)

Natural pyriodxine is found in high amounts in beef liver, organ meats, salmon, dark leafy greens and chickpeas. Synthetic B6 typically utilises formaldehyde and coal tar esters in its production.

Vitamin B7 (Biotin)

Great food sources of natural biotic include beef liver, chicken liver, eggs, salmon, sweet potato, avocados and nuts and seeds. Synthetic biotin is made from from fumaric acid (trans-1,2-ethylene).

Vitamin B9 (Folate) 

Natural folate is found in good amounts in beef liver, chicken liver, dark leafy greens, fruits, seafood and beans. Synthetic folate is called folic acid, can come from petroleum derivatives and acetylene.

Vitamin B12 (Cobalamin)

Natural B12 is found in high amounts in beef liver, oysters, eggs, muscle meat and fish. Synthetic B12 commonly called cyanocobalmin, is create through fermentation with the addition of cyanide.

Vitamin C (Ascorbic Acid)

Natural vitamin C is a complex molecule and is found in good and bioavailble amounts in kakadu plum, acerola berry, black currant, camu camu, oranges, citrus fruits and chicken liver. Synthetic vitamin C only contains an isolated part of ascorbic acid (less bioavailable) and is often dervied from genetically modified corn, a crop heavily sprayed with pesticides.

Vitamin D (1,25-dihydroxyvitamin D) 

Vitamin D is a hormone and not a vitamin. Your best way to get vitamin D is from the sunlight. Food sources are not as efficient as sunlight but good sources of D3 (active form) are cod liver oil, sardines, salmon, beef liver and eggs (mainly the yolk). Synthetic vitamin D is typically dervied from sheep wool wax or alternatively from lichen, which is a combination of fungi, algae and cyanobacteria.

Vitamin E (d-alpha tocopherol)

Natural vitamin E is found in good amounts in walnuts, almonds, peanuts, pumpkin, beet greens and other leaky vegetables like spinach. Synthetic vitamin E (dl-alpha-tocopherol or alpha-tocopherol) is typically sourced from petroleum or in some circumstances extracted from seed oils.

Vitamin K (Menaquinones or Phylloquinone)

There are two natural forms of vitamin K. Good sources of Menaquinones are beef liver, sauerkraut, natto and chicken. Natural sources of Phylloquinone include dark leafy green vegetables like broccoli. Synthetic vitamin K is manufactured by condensing naphthoquinone with isoprenoid precursors.

2. Synthetic Vitamins Can Contain Nasty Additives

Additives are compounds or chemicals which are commonly added to vitamin and mineral supplements to reduce costs, improve taste or colours and help with shelf life. Some of these additives include things like artificial flavours, emulsifiers, vegetable oils, gums and much more. In Australia, companies are only required to list the active ingredient used in vitamins and minerals and not the additives used in the product like you might see on food labels. Two of the most common multivitamin supplements In Australia contain the following additives:

Common Multivitamin A (27 Excipients/Additives)

Acacia, allura red AC aluminium lake, aluminium sodium silicate, butylated hydroxytoluene, calcium hydrogen phosphate dihydrate, citric acid, crospovidone, dl-alpha-tocopherol, Gelatin, hypromellose, indigo carmine aluminium lake, liquid glucose, magnesium stearate, maize starch, maltodextrin, medium chain triglycerides, microcrystalline cellulose, polysorbate 80, potable water, silicon dioxide, sodium ascorbate, sodium citrate dihydrate , spray-dried glucose syrup, starch sodium octenyl succinate, sucrose, titanium dioxide, triacetin

Common Multivitamin B (23 Excipients/Additives)

Acacia, Carnauba Wax, crospovidone, dl-alpha-tocopherol, hypromellose, iron oxide red, iron oxide yellow, macrogol 400, macrogol 6000, magnesium stearate, maize starch, maltodextrin, medium chain triglycerides, microcrystalline cellulose, pea Starch, povidone, purified water, rosmarinus officinalis, silicon dioxide, sodium alginate, spearmint oil, sucrose, titanium dioxide

While many of the hiddens have been linked to negative health outcomes we will cover just a few which can cause issues for you and your health.

Titanium Dioxide

Titanium dioxide is an additive that enhances the whiteness or opacity of certain foods and compounds used in supplements. It has a nanoparticle size between 200 to 300 nanometers giving it a powerful light scattering ability (1). It has recently been banned in Europe over concerns of genotoxicity.

In animal and in vitro studies, titanium dioxide nanoparticles have been shown to induce tumour like phenotypes in human endothelial cells along with impacting microorganisms in the gut (2)(3)(4).

This has lead to concerns that titanium dioxide could induce intestinal inflammation and be a risk factor for colorectal cancer (5). Perhaps one of the most concerning elements of titanium dioxide is that it has been shown to cross the blood brain barrier (6).  

Butylated Hydroxytoluene (BHT)

BHT is is a synthetic food additives which acts like an antioxidants. It is typically added to food and supplements as a preservative. Long term exposure to high amounts of BHT has been shown to be toxic in animal models with studies reporting problems with kidney, liver, thyroid, lung function and blood coagulation (7).

There has also been some evidence that high doses of BHT may result in adverse reproductive outcomes given its possible impact on the expression of certain male and female hormones (8)(9). A study by Cedars-Sinai Medical Center also found that BHT impacts gut to brain signaling and interferes with our bodies ability to tell us when to stop eating. Therefore, there may be concerns that BHT can lead to overeating and therefore obesity (10).

In animal models, exposure to BHT has been shown to negatively impact female reproduction and has some level of reproductive toxicity via its effects on decidualization of mouse endometrium (11). Again, this was in an animal model but is still something to be mindful of, especially during the prenatal and early stages of pregnancy.

Artificial Colours (Allura Red)

Allura Red is one the most common food colourings. Like the majority of other artificial dyes, it is derived from petroleum. It is currently banned in many European nations. Again, Allura red and other artificial colours have been linked with ADHD (12). One study has stated that this particular food dye has been linked to several adverse health effects including allergies, food intolerances, ADHD, nausea and asthma given which may occur in reaction to aromatic azo compounds (13).

Allura red has also been linked to adverse cognitive and neurobehavioral effects in animal offspring (14). In another study, Allura red and other red colourings were shown to exhibit DNA damage in the colon at a low dose in pregnant and male mice (15). It has also been linked to poor reproductive success (16). Artificial colours in general seem to be poorly tolerated to humans.

Citric Acid 

Citric acid by itself does not seem to have too many negative health consequences. Generally cirtric acid is not derived from citrus fruits but is actually produced using a type of mould Aspergillus niger, which has been shown to cause black mould on the surfaces of some fruits. If you have mould issues or inflammatory issues, citric acid might be something to be mindful of consuming.

Polysorbate 80

Polysorabte is a common emulsfier that is usually derived form a mixture of corn, palm oil and petroleum. Polysorbates are used as an emulsifier, stabilizer, and thickener in foods. There has been evidence in animal models that emulsifiers like Polysorbate 60 and 80 are linked with Crohns disease (17). In fact, one hypothesis suggests that the increase in Crohns disease may be the result of emulsfiers being increasingly added to food (18).  


Maltodextrin is a white powder which is often sourced from wheat, potato starch, corn and rice. Unless otherwise mentioned on the label, expect maltodextrin to be sourced from a GMO source as opposed to an organic one. Similar to other additives, maltodextrin is often used as a filler or thickener and has a high glycemic index (will spike insulin). Maltodextrin may also be cause for concern for our gut health. In one in vitro study, maltodextrin was found to increase E.Coli activity which has been linked with Crohn's disease lesions (19). Similarly, in animal models have shown that maltodextrin may promote Salmonella survival by suppressing anti-microbial defence mechanisms (20). Ultimately, the evidence is tracking in the direction of maltodextrin may cause issues for the microbiome (21). However, it is hard to know what dose would lead to these outcomes and whether smaller amounts in supplements would induce such changes but it is something to be mindful of.

Macrogol (400, 6000)

Macrogol is also another name for PEG which is polyethylene glycol. It is used in as a solvent, plasticizier, surfcuant and can also be used as a laxative. This is why you may experience a ‘detox’ like effect to some vitamins. It is unlikely to be a result of the vitamins itself but rather the presence of Macrogol as an additive. In rare circumstance, some people have experienced anaphylaxis to Macrogol 6000 but of course this is unlikely (22).

Medium Chain Triglycerides

Medium chain trgiylcerides on their own are not the worst and in some instances can providie beneficial health effects. However, there are different sources of medium chain tricglyerdies. The best source if from pure extra virgin coconut oil. This is the most expensive option so is rarely used as an additive. The two most common sources of MCTs are either dairy fat or palm oil. Often times, MCT oil if it comes in the form of a power will also be cut with a bulking agent like acacia fibre.

While it is important to avoid the worst additives, sometimes the benefit of the active ingredient will override the importance of avoiding additives all together. For instance, it will be very rare to find a supplement without any additives whatsoever (unless it is just a food like freeze dried beef liver). However, there are certain additives like the ones listed above you should not tolerate as they are often unnecessary and there are always cleaner alternatives available.

3. Synthetic Forms Of Vitamins May Cause Health Concerns

Alongside bioavailability concerns, sometimes the body just does not know how to utilise synthetic forms of vitamins. Afterall, some forms of vitamins found in vitamin supplements are not found in nature. It makes sense that the body is unsure what to do with. Naturally, when the body does not recognise a synthetic vitamin it may lead to health concerns. Now this isnt to say that synthetic vitamins do not have their place but generally the form of synthetic vitamin used in common vitamins is not that great and can also cause more issues then its worth.

Folic Acid

There are close to no concerns with folate naturally found in food. However, there are a few health concerns associated with folic acid. This make sense as folic acid is not present in nature. One of the main concerns is that some people struggle to convert folic acid into folate in the liver (23). This is mainly thought to occur because of low enzyme activity. Comparatively, the natural folate found in food skips this step and is metabolised in the small intestine. The inability to break down folic acid in the liver can result in unmetabolized folic acid, which may cause issues, given it enters the systemtic circulation. 

Generally speaking, folic acid has been linked to an increase prevalance in cancer (24). For example, one meta analysis looking at folic acid consumption in the absence of food fortification found a borderline signifcant increase in the frequency of over cancer compared to controls (25). Of note was one study which showed that daily supplementation with 1mg of folic acid was connected with an increased risk of prostate cancer (26). Other observational studies also suggest a link between folic acid food forticiation and colon cancer (27) . 

Outside of the general population, we know that folate is incredibly important for preventing midline birth defects in babies. However, natural folate should be prioritised over folic acid with some studies connect with elevated risk of tongue ties and autism (28). Instead look for high quality food sources of folate like beef liver or dark leafy greens.

Ferrous Sulphate/Fumerate (Iron)

Synthetic forms of iron commonly found in iron and multivitamin supplements can be problematic. For one, a meta analysis looking at ferrous sulphate showed that supplementation causes significant gastrointestinal side effects in adults (29). 

On top of this, the dose in iron and multivtamin supplements can make things worse and even have the opposite effect by reducing iron levels. For example, one study showed that doses of 60mg or more of synthetic iron increases something called hepcidin for 24 hours which can lower iron absorption the next day (30). 60mg or more is a dose commonly found in typical iron and multivitamin supplements. 

So what is a better alternative? One solution is correcting nutritional deficiencies and getting more haem iron into your diet, which is the most bioavailable form of iron. Beef liver is a great way to increase iron levels naturally. This is because it contains all of the important cofactors required for iron absorption. Beef liver is also high in vitamin A. One great meta analysis showed that vitamin A supplementation alone (in the absence of iron) reduced anaemia risk by 26% (31). It did this by improving hemoglobin and ferritin levels in individuals with low serum retinol levels (32). The role of vitamin a and iron is commonly overlooked.

Albeit in lower amounts, beef liver also contains okay amounts of wholefood vitamin C which has been shown to help with iron absorption (33). Although, a recent study suggests the importance of vitamin C for iron absorption is not as significant as first thought and is comparable to iron supplementation alone (34).

Retinyl Palmitate or Retinyl Acetate (Synthetic Vitamin A)

The main concern surrounding synthetic vitamin A has to do with evidence that high amounts consumed during pregnancy may be linked with an increased risk of birth defects.  Before addressing synthetic A, it is important to state that you should not fear natural vitamin A. All the studies looking at the adverse effects of vitamin A have mostly looked at the synthetic form and even some of these studies have not been able to establish a consistent upper limit and replicate findings. For more on this check out our article debunking the fear around vitamin A during pregnancy.

Overall, there may be an elevated risk of some birth defects with elevated consumption of synthetic vitamin A but studies have not been able to agree on a threshold. The original 1995 study which started the fear surrounding vitamin A has many issues. It concluded there was an elevated risk of birth defects at around 10,000IU of daily synthetic A (35).

However, later studies have shown that supplementation with vitamin A exceeding 10,000IU actually reduced the risk of birth defects. For example, one study showed supplementation up to 40,000IU actually reduced the risk of of birth defects by half while amounts over 40,000IU increased the risk of birth defects by 2.7% (36). Other studies seem to find consensus around 30,000IU perhaps being the upper limit (37) (38) (39). Bearing in mind, these studies mostly focus on the synthetic form of vitamin A.

There has been little no evidence that natural forms of vitamin A have a negative effect, which is why they should be the preferred source. For example, one study looking at vitamin A from fortified food and liver found no connection with birth defects (40).

Beta carotene (Synthetic Precursor to Vitamin A)

There is some evidence that synthetic beta carotene may be linked with an increased risk of mortality and lung cancer. In one double blind, placebo controlled study, Finnish researchers gave male smokers synthetic beta carotene and vitamin E. In those who received beta carotene, there was an 18% increased risk of developing lung cancer and and 8% increased risk of total mortality (41). Interestingly, all formulations were artificially coloured with quinoline yellow which again could be a confounding variable and why hidden additives may be a concern. 

Getting beta carotene from natural sources is best with one study showing smokers consuming food based beta carotene had a reduced risk of Alzheimers disease (42). However, sometimes food based beta carotene will cause issues for people. This is not because of anything found in the food but because a large portion of the population is unable to effectively convert beta carotene (vitamin A precursor) into the active retinol form of vitamin A (43). It is thought upwards of 42% of people may carry this genetic mutation (44). This is why natural preformed sources of vitamin A are best which include things like beef liver, salmon and cod liver oil.

Magnesium Oxide, Zinc Oxide, Calcium Carbonate 

Often times, companies will use cheap forms of vitamins that have really poor absorption rates. Buying multivitamins or supplements with these is like peeing out money. People think they are getting good levels of certain vitamins and minerals but do not realise the form being used might not be moving the needle or might even be making deficiencies worse. 

For example, one animal study showed that only 15% of magnesium oxide administered orally is absorbed with the remainder excreted in feces (45). Older studies suggest that human absorption may even be lower and also be a laxative (46). Zinc oxide is also poorly absorbed at around 49.9% which is the lowest amongst the different types of zinc (47). In this one study, some participants absorbed little to no zinc oxide.

Calcium carbonate is another form of calcium which is basically rocks. It is poorly absorbed by the body with calcium citrate being absorbed 25% more (48). However, studies show that calcium supplements can significantly reduce iron absorption which is why those with iron deficiency should check to see if their supplement contains calcium (49). Ultimately, zinc, magnesium and calcium and other minerals are best absorbed through food sources like oysters, nuts and seeds, sardines, organ meats and other good sources of minerals with cofactors.

4. Bioavailability Studies Suggest Natural Vitamins May Be Better Absorbed

Given synthetic vitamins are crystalline in structure or isolated, they are not as well absorbed as vitamins which come in their natural forms. This is because most vitamins in food come with additional cofactors, enzymes, peptides, trace minerals and are accompanied by complex carbohydrates, proteins and lipids.

Synthetic vitamins on the other hand are devoid of these additional nutrients. They contain no food components. This is typically why lower amounts of food based vitamins are needed to elicit the same result as their synthetic counterpart. 

Nutrition studies often lack funding and require a large amount of resources so the studies looking at absorption comparing synthetic and natural are limited. The evidence we do have suggests that natural forms of vitamins are more bioavailable in most instances. 

Vitamin C is a good example of this. When we look as ascorbic acid (synthetic C) verses naturally vitamin C these are completely different. This is because the makeup of food based vitamin C is not just ascorbic acid but also includes things like ascorbigon, tyrosinase, j factors, k factors, p factors, rutin and bioflavonoids.


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