Consider the common onion. Its medicinal powers stretch back through the ages. It’s been confirmed that humans were eating onions 7000 years ago, since old preserved onions have been found in human settlements from 5000BC alongside stones from figs and dates.
During the first Olympics in Ancient Greece in the first century A.D., the athletes reportedly ate onions for a strength booster. The Pharaohs of Ancient Egypt believed that the spherical shape symbolised eternal life, and demanded that their underlings buried one with them in their tomb.
By the Middle Ages onions were widely used as a currency for goods and services. Combining onions with crushed aspirin and water was once a folklore remedy for warts. New York City was once called the big onion, not the big apple. Another folklore belief relates to the weather. Farmers believe that the quality of an onion can predict the severity of the forthcoming winter, with thinner layers of the onion indicating a harsh season to come.
Clearly, onion is one interesting vegetable. Out of all vegetables, onions are most structurally similar to garlic. They both have a vast array of complex compounds, being full of a variety of flavonoids, anthocyanins, and sulphurous molecules…
…but this complexity and richness can also be the onion’s downfall. Onion is one the otherwise healthy foods that is heaviest in FODMAPs, a natural, plant-derived acne causing menace.
The reason why onions trigger acne outbreaks
If you’ve ever noticed random outbreaks of acne from eating onions, then FODMAPs are the explanation. Specifically, red, white and yellow onions are all heavy in the oligosaccharide form of FODMAP called the fructan.
Firstly, what is the whole problem with FODMAPs for acne? Read this article and you’ll find out. Essentially FODMAPs are different forms of short-chain carbohydrate which the human digestive system cannot fully digest. In most human beings, our gut bacteria steps in to ferment and metabolise them instead, with no harm done. The problem is that many people these days have insufficient healthy gut bacteria, or a stronger adverse response to indigestible carbohydrates.
People with FODMAP sensitivities, an estimated 35% of the population, experience bloating, gas, abdominal pain, and inflammation when they eat onions, garlic, apples, watermelon, artichokes, or other foods rich in these compounds…
…and one of the classic symptoms is acne. The correlation between digestive problems and acne is as tight as the one between kale-only diets and hippies (never listen to them). First you have excessive production of inflammatory chemicals in the gut, which leads to inflammatory chemicals on the face.
Then you have leaky gut syndrome, behind weakened vitamin and mineral absorption and unregulated absorption of unwanted toxins. Lastly, there’s an overgrowth of unhealthy gut bacteria, which churn out stress hormones, inflammatory chemicals, wipe out friendly bacteria and more.
Onions are among the richest foods in one of the most notable FODMAPs, fructans. The main FODMAP groups are as follows: polyols like maltitol and sorbitol, found largely in fruits. Monosaccharides like fructose, found in all fruits. Disaccharides, solely including the lactose found in dairy.
Finally, there’s oligosaccharides, including galactans, raffinose and fructans. Your common onion is almost devoid of all the aforementioned FODMAPs, but they can cause plenty of acne just with the fructans.
A fructan is a chain molecule consisting of the dietary sugars fructose and glucose. Humans lack the correct digestive enzymes to fully break down members of the oligosaccharide group. It’s estimated that only 5-15% of fructans are fully absorbed.
As bacteria in the large intestine ferment the remaining ones, they 1) produce an osmotic effect, sucking in water and 2) churn out methane, carbon dioxide and other by-products as metabolites. What’s more, fructans can preferentially fuel bad bacteria in the gut, feeding their dominance.
Fructans cause all the digestive inflammation and impaired nutrient absorption which is behind people’s acne everywhere. For instance, it has been estimated that 24% of irritable bowel syndrome patients are sensitive to fructans (study); IBS frequently correlates with irritated pimples. This study found that restricting dietary fructans could benefit a wide variety of GI disorders.
This study was the most interesting. It found that independent of fructose intolerance, lactose intolerance, and pathogenic bacterial overgrowth, fructans still had strongly negative effects on gastro-intestinal health.
Not everybody is sensitive to fructans, but for those who are sensitive, they’re serious villains. Onions are one of the richest foods in fructans with ease. They’re beaten by garlic, Jerusalem artichoke and rye grain, with 17.4%, 16-20%, and 4.6%-6.6% respectively. However, onions still contain a strong 1.1%-10.1% concentration of this acne-causing compound.
Onions are packed with FODMAPs by their very nature, as they’re a bulbous root plant. Members of the alliaceae family like garlic and onions all tend to be higher in FODMAPs compared to say, a tuber like a potato.
What’s more, fructans can have two forms. When the molecular chain is short, they’re called oligofructose. When the molecular chain is long, they become inulin, not to be confused with the important acne hormone insulin. Onions’ high fructan count is made all the more damaging by the fact that it’s mostly in the inulin form; extra molecular length is even harder to digest.
The FODMAP diet has gathered steam in the medical community over approximately the last decade; onions are one of the first plants to be exorcized by doctors (apples are another).
If you’ve ever eaten a soup, a salad, or meat sauce containing onion, and witnessed an explosion of acne within hours, then fructans are the reason why.
In turn, it’s highly likely that you have a bacterial imbalance, a weakened gut lining, or another problem contributing to FODMAP sensitivity which requires addressing…
The alternative – onions may improve your gut health
…and here’s where things get interesting. If you are not sensitive to fructans, then fructans can be a fantastic compound for acne. That means that onions can be a stellar food and eating them more can be a great strategy for your skin.
The reality is that the processes with fructans and other FODMAPs never change. Your gut bacteria will always metabolise the majority of them. But what can change is the quality of your gut flora. If you have the correct strains and volume of bacteria, almost all of the FODMAP varieties can have probiotic effects. They provide fuel for good bacteria which metabolise them and allow them to expand their influence, not the pathogenic ones on a mission to create pimples.
For that reason, for the majority of acne patients, eating more onions can be one of the best prebiotic strategies of all time. Inulin has been shown to stimulate the growth of beneficial bacteria, resulting in a decrease in toxic metabolites inflammation. Gut bacteria are known to convert inulin into short chain fatty acids such as butyrate, with anti-inflammatory, insulin sensitivity enhancing properties. Inulin supplementation was observed in two studies to lower levels of inflammation in patients with Crohn’s disease. Benefits for inflammatory bowel disease have also been observed.
In a more indirect benefit, inulin supplementation increased the absorption of the mineral calcium in both boys and girls aged 9-13. That’s an expected benefit from fuelling healthy bacterial strains, since they can protect the integrity of the gut lining. If calcium became more efficiently absorbed, then so might the two most effective acne minerals, zinc and selenium.
Inulin is a real Jekyll and Hyde substance – an inflammation-promoter in the FODMAP sensitive, a soothing probiotic in everyone else.
Studies on onions themselves have also been promising. This one found that onion oil acted like an antibiotic by wiping out toxic bacteria and yeasts.
Onions are also one of the common foods richest in quercetin. Quercetin is manufactured by onions to protect cells against UV light; it’s most concentrated in the outer layers for that reason. Its chief function is as an antioxidant, but in studies on humans, it has a variety of gut-protective effects.
Firstly, it can increase the responsiveness of tight junctions which maintain gut barrier function. Secondly, quercetin acts as a natural anti-histamine; it decreases the pro-inflammatory activity of mast cells in response to falsely identified “threats”. This decreases the risk of pointless allergies to perfectly safe foods, the type of allergy that can trigger acne.
The quercetin in onions is highly bioavailable as well. This human study compared the quercetin of apples and onions: “the bioavailability of quercetin from both apples… was 30% of that of quercetin from onions”. Approximately 52% of the onion quercetin was absorbed in humans. If you’ve read many of these bioavailability studies then you’ll know what an excellent figure that is.
The scientists also concluded that molecular conjugation with glucose enhances the absorption of quercetin from the small intestine. Good news – the most common forms of quercetin in onions include quercetin-beta-glucosides. When protecting against leaky gut syndrome, you need quercetin IN the gut anyway, so an even larger proportion than 52% will be working its wonders.
The best part about this? Onions have far more quercetin than apples anyway. Boiled onions and raw red onions contain 19.36mg and 19.93mg per 100 grams compared with 4.42mg per 100 grams in apples.
If you have no FODMAP sensitivity, then the combination of quercetin and inulin makes onions one of the best gut protecting foods, on several fronts.
Onions – one of the most sulphurous vegetables
Outside of the realm of gut health, which is still being researched for its effect on acne, onions are also excellent for increasing your antioxidant supplies.
Their first line of attack is their high content of sulphur. Onions are rich in organosulfur compounds like allinase, alliin, diallyl trisulfide and diallyl sulfide. The most famous is allicin, a sulphurous substance also found in garlic which metabolises into sulfenic acid, one of the most potent antioxidants yet discovered. But what makes the sulphur aspect so important?
Dietary sulphur is a key ingredient of the indigenous antioxidant glutathione. Unlike quercetin or vitamin C, glutathione is manufactured by the human body, and you need sulphur to do it. The sulphurous supplement MSM works well for that reason, as do cruciferous vegetables such as broccoli with sulforaphane.
This study on onions analysed its effect on cellular glutathione levels. 6 weeks of daily consumption of an onion extract was found to increase not just glutathione, but also the antioxidants catalase and superoxide dismutase. Malondialdehyde, a marker of free radical activity, was substantially decreased. Garlic achieved similarly great results. The conclusion: “these findings suggest antioxidant enhancing capability for both doses of onion and low dose of garlic”.
You eat a pomegranate, you get pre-formed anthocyanins. You eat potatoes, you get pre-formed vitamin C. Onions and garlic are among the most potent plant foods full-stop for helping you to manufacture your own antioxidants.
What’s more, they contain a vast treasure chest of pre-formed antioxidants themselves. We’ve already covered one of them, quercetin. Specifically quercetin is a flavonoid antioxidant, and according to this review, onions contain 25 forms of flavonoids in total. The two major classes of antioxidants in onions are flavanols and anthocyanins; both have around 25 sub varieties each. Yellow onions are inferior with 270-1187 mg of flavanols versus 415-1917 mg for red onions, but both results are stellar. The flavanols are said to be the predominant pigments of onions as well.
One study analysed the effect of an onion marinade applied to fried meat on the formation of heterocyclic aromatic amines. HAAs are a prime worry among primal living fanatics; they’re oxidising compounds formed when the harsh heat of frying reacts with proteins. They’re linked mildly with cancer and importantly for acne, antioxidant depletion.
Luckily, plenty of strategies for preventing HAAs exist, and an onion marinade is one of them. The study observed that onion was almost equal to garlic in tackling HAA formation. Lemon juice was actually more effective than both (just don’t put it on your skin).
What does this study provide? Yet more evidence of the onion’s antioxidant powers.
How can you tell whether onions are safe?
The most effective way to tell is the most simple. Eat one and observe whether you have adverse reactions.
It could be fast, new pimples forming within hours. It could be more insidious; you might observe a rumbling stomach and a dull ache after a week of eating onions every day.
If you are sensitive to other FODMAP rich foods, then the chance that you will react to onions is also dramatically higher. The other foods rich in fructans are garlic, rye, artichokes and wheat. For a full list of foods rich in FODMAPs, read the full article, but a few examples are apples, blackberries, watermelons, cabbage and asparagus. Lactose in dairy is another one.
The circumstances that lead to a FODMAP sensitivity are equally numerous, but one good example is a high sugar intake. Take a look at your diet. If you eat in excess of 125 grams of sugar per day, then that will be providing a feast for all the pathogenic bacteria and yeasts like candida in your gut. A high sugar diet = bad microorganism overgrowth, and possibly a FODMAP sensitivity.
If you are actively attempting to heal your gut, possibly with the instructions in my eBook Annihilate Your Acne, then onions should be avoided in the earliest stages. However, at a certain stage, the scales will tip and onions will become beneficial for acne; it all depends on the balance between acne-friendly and pathogenic bacteria. Probiotics like yoghurt, sauerkraut, natto, and kefir can thus bring the day you can eat onions closer again.
There are too many factors involved with FODMAP and fructan sensitivity to fully explain here, so a final alternative is to experiment.
You can eat onion daily in a salad or soup for a week, and examine the results. Then remove all onions for a week while maintaining the exact same diet otherwise. Analyse both your acne AND your digestive health and comfort. Use your own instincts and work out whether onions are a problem for you.
The guide – how to make your onions the healthiest
The first excellent piece of news is that buying onions organically is totally pointless. Conventional onions have extremely low pesticide quantities. The species repels pests completely, just like garlic.
Some gardeners have been scratching their heads and wondering why the only species that eats onion is the human. Some have even got worried, thinking that we’re making a mistake and humanity is finished. However, the glorious truth is that pests cannot stand organosulfur compounds; garlic is used as a natural pesticide for that reason.
In the 2016 edition of the “clean fifteen” agricultural products free from agrochemical (pesticides, herbicides, insecticides, fungicides) contamination, onions were ranked 6th. Just 0.3% of conventional onions tested for pesticide residue came up positive.
What’s more, organic cultivation had zero effect on polyphenol antioxidant levels in this study. No statistically significant differences were found between growth systems. Organic cultivation increases vitamin C and antioxidants in fruits like strawberries and bell peppers, but not onions. If your supermarket sells organic onions, it’s nothing more than a sleazy cash-in.
What is significant however, is the differences between varieties of onion. Yellow onions, which account for 87% of US production, contain roughly 11 times more antioxidants than white ones (5% of production). Red onions are closely ahead of yellow in their antioxidant capacity.
Don’t mindlessly follow conventional wisdom; peel as little of the outer layers as you can. Why? The antioxidants are generated as defences against UVB radiation; you don’t want to peel away those defences.
This study also revealed that small onions had a higher flavonoid content per kilogram than larger ones. My theory is that at some stage of the maturation, growing onions reach a set quantity of antioxidants which becomes dispersed as they expand; in that case you’d be better off buying four small ones as opposed to two large ones.
Cooking method also has significant effects. This study found that with different cooking methods, the decreases in onion quercetin content were as follows: frying, 33% sauteing, 21, boiling, 14-20, steaming, 14, microwaving, 4, baking, 0. It seems like boiling is a decent enough way to go, meaning that you can add your onions to an acne-friendly soup recipe.
What’s more, this study revealed the truth of the matter. Boiling onions led to a 30% decline in the quercetin content. The question is, where did it go? Into the water. Quercetin is a water-soluble antioxidant, so if you cook your onions into an acne-friendly soup packed with other nutritious vegetables, you won’t miss out on anything.
Next, you have to buy your onions fresh from the market. Commercial, dehydrated onion products contain low amounts or even zero flavonoids. Onion powder will have lost its beneficial compounds as well, so don’t get tempted to pour some into soup; the allicin only stays active for 24 hours.
Which brings us to the next point – with onions it’s smart to adopt the same tactic as garlic where you slice into your bulb only immediately before using it.
Allicin, among the most potent organosulfur compounds in onion, is produced when the enzyme allinase reacts with alliin. Allinase is found in different cells to alliin, cleanly separated by the cell walls, so the reaction occurs immediately after slicing the root with a knife. However, the resulting allicin is extremely unstable, degrading to almost nothing within 24 hours thanks to its awful half-life.
The solution? Use your onion within hours of slicing it, for maximum antioxidant effect against acne. There’s no problem with keeping a whole onion stored in your cupboard, but once the perimeter has been breached, get it in your body as fast as you can.
No matter your circumstances, it’s pretty likely that onions will do something to your acne. They can either be your best friend, or your worst nightmare.
Despite being natural, FODMAPs are never a foe to be taken lightly. They can generate acne just as swiftly and strongly as a sugary mars bar or greasy plate of frankfurter and fries.
However, if you can tolerate them, onions are truly great for acne, preventing pimple formation in the first place thanks to their antioxidants.
This saga also illustrates the greatness of variety in an acne-clearing diet. Kale and onions both share the sulphurous compounds, with sulforaphane versus allicin. But kale also has over 100% of the daily allowance for vitamin A, the greatest nutrient for oily skin.
Onions, meanwhile, contain inulin and can feed your acne-friendly bacterial colonies. These probiotic effects makes the onion a highly distinct vegetable from broccoli or spinach.
Thanks for reading!