The Ingredient Behind a Century of Chronic Disease — On Your Plate and In Your Products

Important note: This post is for educational and informational purposes only. Nothing here constitutes medical advice. Julie is a holistic nutritionist sharing her research and perspective, not your doctor.

Here's the principle I build every single formula around, and I've never said it quite this plainly before: I won't put anything on your skin that I wouldn't put in your body. Your skin absorbs what touches it. If an ingredient needs a laboratory to exist, if I can't pronounce it, if it started as something recognizable and got chemically transformed into something else entirely — it doesn't belong in a Magnolia Crow jar, and honestly, I don't think it belongs on your plate either. Nothing embodies that line better than hydrogenated oils, so let's actually walk through what they are, what they do to your body, and yes, what they're doing in a shocking number of skincare products too.

WHAT HYDROGENATION ACTUALLY IS

Hydrogenation is an industrial chemical process, not a cooking technique. Manufacturers take a liquid vegetable oil and, under high heat and pressure, bubble hydrogen gas through it in the presence of a metal catalyst. This forces hydrogen atoms onto the oil's unsaturated fat molecules, converting a liquid oil into a solid or semi-solid fat — shelf-stable, cheap to produce, and resistant to spoilage in a way the original liquid oil never was.

This isn't a small tweak. The resulting fat barely resembles the plant it came from. Procter & Gamble introduced the first major hydrogenated shortening — Crisco — in 1911, and hydrogenated oils have been quietly embedded in the food supply ever since: margarine, packaged baked goods, crackers, frosting, coffee creamers, and anything else that benefits from being cheap and shelf-stable for a long time.

THE CENTURY-LONG TIMELINE

Here's the historical picture, laid out plainly: in 1900, seed oils accounted for roughly 1% of added fat in the American diet. By the end of the century, that figure had climbed to approximately 85%, with hydrogenated versions forming a major share of that shift, especially in processed and packaged foods. That's not a minor dietary adjustment. That's a wholesale replacement of the traditional fats — tallow, lard, butter — that had fed people for generations, swapped out for an industrially manufactured substitute in the span of a few decades.

And the timeline of chronic disease tracks right alongside it. U.S. adult obesity sat at roughly 13% in the early 1960s. Today it's over 40% — more than tripled. Type 2 diabetes, once considered a disease of later adulthood, now shows up regularly in children. I want to be careful here, because I think intellectual honesty matters more than a satisfying villain: chronic disease has many contributors, and I can't hand you a single study proving hydrogenated oil alone caused this shift in isolation. Diets changed in a dozen ways over the same period — more sugar, more refined carbohydrates, less physical activity, more ultra-processed food generally. But the introduction and rapid, near-total takeover of hydrogenated and industrially processed oils sits squarely inside that same timeline, and I don't think that's a coincidence worth dismissing either.

THE TOXIC BYPRODUCT: TRANS FAT

Here's the part of this story that isn't up for debate. Partial hydrogenation doesn't just solidify oil — it creates trans fats as a direct byproduct of the chemical process. Trans fats are consistently and strongly linked to heart disease, more so than almost any other dietary fat, which is exactly why the regulatory response was so decisive.

The regulatory response reflects just how strong that evidence became. Denmark essentially banned partially hydrogenated oils back in 2003. The U.S. FDA required trans fat disclosure on nutrition labels starting in 2006, then in 2015 made a formal determination that partially hydrogenated oils are not "generally recognized as safe" for use in food at all — a designation one public health researcher bluntly summarized as the FDA officially confirming what everyone already understood: this ingredient was "generally recognized as dangerous." Manufacturers were given until 2018 to remove it from the food supply.

Even now, a labeling loophole is worth knowing: U.S. food labels can list "0g trans fat" if a single serving contains less than 0.5 grams. Eat multiple servings of something containing partially hydrogenated oil, and you can still take in a meaningful dose while every package technically said zero. Reading the actual ingredient list for "partially hydrogenated" — not just trusting the nutrition panel — is still worth doing.

THE GUT-SKIN CONNECTION: WHY A DIETARY FAT SHOWS UP ON YOUR FACE

This is where I want to bring back everything we've covered before on this blog about the gut-skin axis, because it applies directly here.

Diets high in industrially processed fat have been shown, in both animal and human research, to weaken the gut lining, making it more permeable than it should be — what we've called "leaky gut" in previous posts. Once that barrier loosens, things that should stay contained in your gut start leaking into the rest of your body, triggering exactly the kind of low-grade, body-wide inflammation that shows up in downstream tissue — including your skin.

The skin side of this connection has real support too: the beneficial compounds your gut bacteria produce when they ferment fiber have been shown to directly strengthen your skin's outer barrier. A diet heavy in processed, hydrogenated fat and low in the fiber that produces those protective compounds pushes that whole system in the wrong direction at once — more gut permeability and inflammation, less of the protective support that keeps your skin barrier resilient. This is precisely the kind of mechanism that can turn a purely dietary choice into a very visible skin eruption weeks later, with no obvious topical cause in sight.

HYDROGENATED OILS ARE ALSO HIDING IN YOUR SKINCARE

This is the part I'll be honest I hadn't dug into as deeply before writing this post — but it turns out hydrogenated oils show up constantly in cosmetic formulations too, not just food.

Ingredients like hydrogenated soybean oil, hydrogenated vegetable oil, and hydrogenated castor oil appear across moisturizers, night creams, lipsticks, balms, foundations, and hair products, prized by manufacturers for the same reasons food companies use them: better shelf stability, a smoother texture, and a cheaper production process than working with a natural wax like beeswax.

I want to be fair to the actual data here rather than overstate it: hydrogenated castor oil specifically has been reviewed by the Cosmetic Ingredient Review panel and generally tests as non-comedogenic and well-tolerated in typical use concentrations. But general "hydrogenated vegetable oil" carries a real, documented comedogenic rating in dermatology references, and its semi-solid, occlusive nature can trap sebum, dirt, and bacteria against the skin — a genuine concern for acne-prone skin specifically. Much of it is also palm-oil derived, tying it to real deforestation and environmental concerns beyond the skin question itself.

But here's where I land regardless of the comedogenicity debate on any one specific ingredient: even the "safer" hydrogenated cosmetic ingredients are still lab-processed substances, chemically transformed away from anything resembling their original plant source, specifically to make manufacturing cheaper and shelf life longer. That's the same industrial logic driving the food-supply version of this ingredient, just wearing a different label. If I won't put it in your body, I'm not going to put it on your skin either — regardless of whether a particular version of it clears a comedogenic testing panel.

WHERE OUR OWN INGREDIENTS STAND

Every oil in our products is cold-pressed and organic — mechanically extracted using pressure alone, no heat, no chemical solvents, no hydrogen gas, no catalyst. It stays in its original liquid form, retains its natural vitamin E and antioxidant content, and never undergoes the chemical transformation that creates trans fats or the semi-solid, occlusive texture of a hydrogenated cosmetic ingredient.

Grass-fed tallow and beeswax, our actual structuring ingredients, are naturally solid at room temperature — no industrial process required to get there. That's not a coincidence or a clever formulation trick. It's the entire reason traditional fats worked for thousands of years without anyone needing to invent hydrogenation in the first place, as we covered in The Fat That Time Forgot.

THE REAL TALK

If you take one thing from this post, let it be the principle I opened with: your skin absorbs what touches it, the same way your gut absorbs what you eat. An ingredient that needed a hydrogen tank and a metal catalyst to exist doesn't get a pass just because it's sitting in a "clean beauty" jar instead of a snack aisle. I'd rather build every formula, and eat every meal, around things that looked like themselves before they reached me.

— Julie Conradt, Magnolia Crow Soap Co.