Spinach is a widely beloved vegetable, with the average American eating roughly 2.5 pounds per year. Women over 40 top the spinach-eating tables, and Americans eat approximately 4 times more spinach than 40 years ago.
Most of its popularity is down to its reputation for extreme, explosive muscle growth. This dates back to a mistake from the 1930s, when German scientist Emil von Wolff accidentally misplaced a decimal point and recorded an iron content in spinach ten times higher than the reality.
Cartoonists were soon inspired to create Popeye the sailor, whose bulging forearms came solely from his spinach obsession. Thanks to Popeye, US spinach farmers enjoyed a 33% increase in sales during the 1930s, and the prominent spinach-growing town of Crystal City, Texas even erected a full-sized statue of Popeye to display their gratitude.
Thanks to this origin story, spinach has the shining reputation of an immensely nutritious leafy green vegetable, standing shoulder to shoulder with the superfood kale. But is it really, and can acne patients like you benefit?
Why spinach is a deceptive vegetable
On the face of it, spinach is an excellent source of acne nutrients.
100 grams of raw spinach contains 20% of the recommended daily intake for magnesium, a mineral which aids sleep and boosts glutathione production. There’s 47% of the RDA for vitamin C, which increases collagen production, and a giant 188% for vitamin A, which lowers oil and pore-clogging keratin production.
However, spinach has one major complication. Spinach is the cruciferous vegetable highest in oxalic acid, a potent mineral-binder that inhibits the absorption of dietary calcium, zinc, magnesium and iron.
Traces of oxalic acid are perfectly normal in plant foods, as strawberries have 34mg per half cup, celery has 35mg per half cup, and broccoli 1.8mg. Usually, their impact is barely felt, but spinach looms over the competition, with 750mg of oxalates per half cup. Only rhubarb, puriane and beet greens contain more, with 860mg, 910mg, and 916mg per half cup respectively.
Read Annihilate Your Acne – get the diet that could transform your skin!
Consequently, because human beings lack the necessary gut bacteria to break down oxalates, spinach’s high 20% content of magnesium is much weaker than it looks. This 2004 study confirmed the problem, feeding 9 healthy people either white bread with 300 grams of spinach, or white bread with 300 grams of curly kale. Kale is also packed with magnesium, but contains only 15% of spinach’s oxalates, with 110mg per 100 grams.
The absorption prophecy was fulfilled, as the magnesium in spinach was significantly less bioavailable than that of kale: 26.7% absorption versus 36.5%. According to the scientists, this was attributed to “attributed to the difference in oxalic acid content between the two vegetables”.
The kale wasn’t amazing itself, as 110mg of oxalates dwarfs broccoli (1.8mg) or Brussel sprouts (37mg). However, with spinach, you only absorb 5% of the RDI for magnesium, when a serving actually contains 20%.
Why the vitamin C is also deceptive
The good news is that oxalic acid only binds to minerals, not vitamins. However, the health dangers of oxalates also mean that you need to cook spinach more than the average cruciferous vegetable.
The most notorious danger is kidney stone formation. In the bloodstream, oxalic acid is strongly attracted to dietary calcium, binding together to form calcium oxalate molecules. These accumulate around the body, and especially in the kidneys, to form hard stones that snowball in size. Doctors routinely prescribe low oxalate diets to kidney stone patients, and spinach is normally outlawed completely.
For acne patients, there’s also evidence that excessive oxalates spike inflammation and can trigger glutathione depletion. Put simply, it’s never good for calcium crystals to be floating aimlessly around your bloodstream.
Next – the 6 best vitamins and minerals for naturally clear skin
Consequently, I recommend that all acne patients cook their spinach thoroughly…
…and that’s where the problem kicks in, because all cruciferous vegetables are vulnerable to nutritional depletion when cooked. This 2000 study found that boiling spinach decreased the vitamin C content by 46.5%, outdoing peas (25.2%) and green beans (18.2%).
A 2013 study found a 10% loss of vitamin C when boiled for 5 minutes (a normal duration for deactivating oxalates), while studies elsewhere suggest a 75% reduction in healthy phytonutrients after boiling spinach for 10 minutes.
Therefore, rather than 47%, spinach provides more like 35-40% of the RDI for vitamin C.
But spinach is still highly nutritious!
That said, 40% is still decent for vitamin C. Better, there’s no evidence that the colossal vitamin A count (great for oily skin) is affected severely.
According to one study, you only need 5 minutes of boiling to reduce spinach’s oxalates by 30-87%. Steaming led to a 5-53% decline. Spinach is still weaker for acne nutrients than it first appears, but the study showing a decline in vitamin C of 47.5% cooked the spinach for a whole 30 minutes. Another study found a 60% decline after 30 minutes. That’s completely unnecessary: 30 minutes would leave you with green slime.
Additionally, seeing as magnesium isn’t warped or depleted by cooking, the deactivation of oxalates will push its absorption higher again, to the equivalent of approximately 10% of the RDI.
This study found that after boiling spinach, the oxalate content fell so far that magnesium was barely affected anymore. Spinach was dubbed “one of the most promising sources“.
Spinach – a top 10 sun protection food
Then there’s spinach’s profile of rare phytonutrients. Spinach is the second best confirmed source of the carotenoid antioxidants lutein/zeaxanthin, which have potent abilities to reduce bloodstream lipid peroxides.
This study concluded that feeding 10mg or 20mg of lutein to non-smokers dramatically lowered their malondialdehyde levels, a bodily marker of lipid peroxidation. That’s excellent news because lipid peroxides are worst free radicals for acne, melting your vitamin E stocks. Lutein/zeaxanthin succeed by being fat-soluble rather than water soluble antioxidants.
This study also found that dietary lutein/zeaxanthin protected rats against sunlight-induced lipid peroxide damage to the skin. Lutein and zeaxanthin (which are grouped together due to being nearly identical) even migrate to the cornea of your eye and protect against age-related macular degeneration there.
7 natural topical treatments which can massively reduce acne
As for spinach, 100 grams contains 15.691mg of lutein/zeaxanthin, which is only beaten by kale (19.686mg), and easily exceeds broccoli (1.080mg) and Brussel sprouts (1.541mg). For mysterious reasons, the lutein content of spinach increases through cooking, whereas in kale it decreases.
Antioxidants are the one area where spinach really shines, as according to this 2003 analysis, spinach defeated every other vegetable in two out of three common antioxidant tests. Raw spinach has an official ORAC score of 1513, which stands proudly next to kale (1770) and broccoli (1510).
The studies on spinach and blood antioxidants are equally promising:
ONE: eight elderly women were fed either 240 grams of strawberries, 294 grams of spinach, 300ml of red wine, or 1250mg of vitamin C (study). Using the ORAC test, bloodstream antioxidants increased by 7-24% roughly 4 hours after eating the foods. Urinary levels of antioxidants increased by 27.5% after eating spinach, compared to 9.6% for strawberries.
Vitamin C levels also increased significantly, but the scientists remarked that this couldn’t fully account for spinach’s antioxidant magic. Clearly, spinach contains other acne-friendly antioxidants.
TWO: next, we have this 2011 study where 8 participants were given 225 grams of spinach for 16 days. Antioxidant protection of DNA increased both 6 hours after consumption and after 11 days of continuous spinach consumption (any volunteers?).
Spinach also decreased the blood content of homocysteine, a notorious amino acid used to measure heart disease which also correlates tightly with oxidative stress. It seems that spinach hoovers up free radicals through many mechanisms.
THREE: this 2014 study fed spinach extract to some rats for 6 weeks, and the result was a big reduction in thiobarbituric acid reactive substances (TBARs), another highly accurate marker of free radicals.
The number of different antioxidants identified in spinach is truly enormous. Lutein/zeaxanthin are carotenoid antioxidants that specifically hunt down lipid peroxides, and other carotenoids in spinach include neoxanthin, fucoxanthin, violaxanthin, and beta carotene.
Spinach’s flavonoid antioxidant catalogue includes jaceidin and patuletin, and even two unique flavonoids called spinacetin and spinatoside. These were only identified recently, so who knows what unique powers they possess?
Spinach boosts your friendly bacteria
Meanwhile, eating spinach is particularly smart if you’re convinced that your acne is connected to poor gut health somehow.
Two interesting studies have caught my eye recently. The first tested thylakoids, hidden compounds wrapped up in spinach’s leafy chloroplasts. These thylakoids have strong appetite-suppressing properties and are even sold as a deep green-coloured weight loss powder.
Rats were fed either a thylakoid-enriched diet or a control diet. 10 days later, the thylakoid group had significantly increased friendly gut bacterial strains, particularly lactobacillus reuteri.
The advantage for acne? L. reuteri suppresses the inflammatory bacteria strain helicobacter pylori, which causes many peptic ulcers in third world countries, but also prevents healthy nutrient absorption.
L reuteri was shown here to control intestinal permeability (AKA leaky gut syndrome), which means less inflammatory molecules flooding into the bloodstream. L. reuteri may have direct anti-inflammatory activity on human epithelial cells (which regulate the absorption of nutrients from food), upregulate an unusual anti-inflammatory molecule called NGF, and inhibit the pro-inflammatory messenger NF-KappaB.
Sea buckthorn oil – a natural secret for acne and oily skin
L. reuteri is a trusted ally of us acne-clearing fanatics, and rare compounds in spinach can apparently increase it. Meanwhile, another batch of spinach compounds called glycoglycerolipids have been shown to protect the gut lining.
Yet another gut-protecting compound
The story doesn’t end there. Recently, I scoured the dark catacombs of the internet and discovered that spinach is packed with quercetin, a water-soluble antioxidant.
In our sweet potato article, we discussed how quercetin suppresses the mast cells in the small intestine which fire out pro-inflammatory chemicals, and is better at doing so than the pharmaceutical drug cromolyn.
It turns out that we’ve only scratched the surface:
ONE: a secretive player in digestive health is the tight junctions, proteins which directly control the opening of the semi-permeable membrane to allow nutrients to pass through and to keep inflammatory molecules out. Quercetin can improve both the quantity and performance of tight junction proteins (2011 study).
TWO: once again, quercetin induced a “strong increase” in tight junction proteins, particularly claudin 4 (2008 study). Claudins are the main family of proteins in the gut’s semipermeable membrane, with 24 members in total. Their individual properties are still under investigation, but quercetin somehow affected claudin 4 at the genetic level. Quercetin had benefits against “barrier disturbance in intestinal inflammation”.
THREE: a nearly identical result: “this study demonstrates that quercetin enhances the intestinal barrier function”. Quercetin was compared to a blueberry flavonoid called myricetin and proved to be significantly better for a leaky gut. Claudin 4 was affected once again, giving us some consistency (2009 study).
Spinach contains 4.86mg of quercetin per 100 grams, whereas raw broccoli contains 3.21mg and kale is even better with 7.71mg. Quercetin can also combat the food allergies behind explosive acne outbreaks.
DOWNSIDE – organic spinach is necessary
The only real problem with spinach, outside of the goitrogens which people blame for thyroid problems (but are mostly safe), is its heavy pesticide contamination.
When investigating 43 different fruits and vegetables, the Environmental Working Group discovered that sweet bell peppers, lettuce, celery, potatoes and spinach were top of the pile for agrochemical residues. Whatsonmyfood.com lists a grand total of 54 different pesticides, including 21 suspected hormone disruptors, 11 neurotoxins, 7 developmental or reproductive toxins, and 20 honeybee toxins. Back in 2015, spinach ranked 7th on the yearly “dirty dozen” list of the 12 worst foods for pesticides (with apples being highest).
The physical explanation is simple. Spinach, kale and lettuce are leafy vegetables, which gives them a very high surface area. There’s endless space for insects to sink their teeth into, and therefore more pesticides have to be sprayed. Consider the square inches exposed to the outside world on spinach leaves versus a whole potato.
Worse, it’s impossible for farmers to wash the pesticides off properly, because the leaves would shred up and fall to bits. Potatoes, meanwhile, are easy to drench and scrub clean without damaging the potato.
The most ubiquitous agrochemical is the insecticide permethrin, a neurotoxin found on 51.9% of spinach samples. The US Environmental Protection Agency (EPA) claims that permethrin is carcinogenic and causes lung and liver tumours in mice. It’s also linked to tremors, loss of coordination and behavioural problems, but most pertinently for acne, glutathione is closely involved in permethrin’s detoxification (study), meaning that constantly ingesting permethrin may deplete your all-important antioxidant supplies (with glutathione being a vital one).
Another common pesticide is DDT, which was banned by the USA in 1972 after cancer and birth defects emerged, but is still shipped out en masse to developing countries in South America where the insects are extra aggressive. Hence, imported spinach still contains DDT, and what’s more, DDT lingers in the soil for decades. Spinach grown in non-organic US fields still comes up positive for DDT occasionally.
Why other vegetables are safer
Compare this carnage to the trusted broccoli or asparagus. Broccoli is sometimes sprayed, but pesticides don’t work as well on the plant, so farmers often don’t bother. Broccoli has dramatically less surface area too. Asparagus, meanwhile, enjoys complete immunity because insects find its taste weird, like marmite.
Zinc – the number one mineral for clear skin (reduces acne by 49.8%)
It’s possible that levels of each individual agrochemical are minimal. and that the sheer nutrition of spinach could make even the conventional version a net bonus for acne. Nevertheless, if you’re determined to avoid all chemical contaminants, then spinach has one unarguable flaw.
Low pesticide alternatives would include sweet potatoes for vitamin A, and broccoli and pineapple for vitamin C. Onions are packed with quercetin, and insects mostly ignore their strong sulphorous aroma.
Alternatively, if you’re a walking cashpoint machine, you can purchase organic spinach. Compared to organic kale, it’s slightly more affordable, at least here in the UK.
Conclusion – the verdict on spinach
The final judgement is that spinach is excellent for acne if you 1) need plant-based vitamin A, 2) are afflicted with digestive woes, or 3) need antioxidants.
Spinach is beaten by broccoli for vitamin C, but dwarfs it for vitamin A. Spinach is particularly promising for feeding your friendly gut bacteria, by raining down quercetin and thylakoids from above. Then there’s its direct powers against acne-causing lipid peroxides. Broccoli, meanwhile, is superior if you cannot afford organic foods.
Remember though, that these comparisons are totally relative. If you’re a newbie whose sole vegetable is currently potatoes, any green vegetable will blast your skin with gamechanging acne nutrition. Boiling spinach for approximately 5 minutes is optimal, to shatter the oxalate crystals and increase magnesium absorption.
NEXT: discover the root causes of acne and banish your pimples forever
Thanks for reading!
This article was so valuable and full of information. Thank you for taking the time out to write. I’ve been experiencing acne breakouts and I’ve never had them, but I’ve also started eating a cup of raw spinach for dinner. I was wondering why my skin was looking bad suddenly whereas it should be cleaner looking. You gave me so much extra information, besides mynoriginal concern. Thank you thank you thank you !!