Eggplant benefits: two cholesterol trials both matched placebo

Key benefits

1. 01Not established

   Two randomised trials — both matched placebo

   This entry is not a benefit but a record that no benefit was established.

   In Brazil eggplant became an established folk remedy for high blood lipids, to the point that dried eggplant powder was sold as a product for that purpose. Two clinical trials followed.

   First, 2000, Brazilian Journal of Medical and Biological Research.

   • 38 people with hypercholesterolaemia, split between eggplant infusion (19) and placebo (19)
   • Five weeks, with total cholesterol and its fractions, triglycerides and apolipoproteins A and B measured at baseline, three weeks and five weeks
   • Result: no differences were observed compared with control
   • An intraindividual analysis did show significant falls in total and LDL cholesterol and apolipoprotein B
   • But after dietary guidance was added, no differences were seen within or between groups on any parameter

   The authors concluded that the effect was "modest and transitory" and no different from what standard guidance for dyslipidaemia — diet and physical activity — already achieved.

   Second, 2004, Arquivos Brasileiros de Endocrinologia e Metabologia. A double-blind placebo-controlled study.

   • 41 people with hyperlipidaemia — 21 on eggplant, 20 on placebo
   • Two 450 mg capsules of dried eggplant powder twice daily, for three months. That dose was the one actually used for hyperlipidaemia in Brazil
   • Result: at three months, total cholesterol, LDL and the LDL/HDL ratio fell in the eggplant group (p<0.05)
   • "However similar effect was also observed in the placebo group"
   • Triglycerides, HDL, VLDL, AST, ALT, γ-GT, glucose and BMI showed no significant change

   The authors concluded that eggplant, in the form sold in Brazil, requires further trials before it can be recommended for hyperlipidaemia.

   Two lessons here.

   First, "I took it and my numbers fell" is not evidence. The numbers fell in the eggplant group in both trials. They fell just as much on placebo. Someone who has started paying attention to their health also changes their diet and activity, and lab values drift on their own (regression to the mean). Without a placebo group, all of that gets misread as effect.

   Second, the standard measures did better. In the 2000 trial, once dietary guidance was given, nothing of the eggplant effect remained. Eggplant added nothing to what diet and exercise were already doing.

   The honest conclusion: there is no evidence that eggplant lowers cholesterol. Eating it is a good thing, but that is eating a vegetable, not taking a treatment.

   [1][2]
2. 02Nutrition data

   25 kcal per 100 g — but look at how much oil goes in

   Per 100 g of raw eggplant:

   • 25 kcal, protein 0.98 g, fat 0.18 g
   • Of 5.88 g of carbohydrate, 3.0 g is fibre, sugar 3.53 g
   • Potassium 229 mg, manganese 0.232 mg, folate 22 µg
   • Magnesium 14 mg, vitamin C 2.2 mg, vitamin K 3.5 µg
   • Sodium 2 mg

   The 25 kcal defines it — a little above courgette (17 kcal) and level with cabbage (25 kcal). A whole medium fruit at 250 g is 63 kcal.

   3.0 g of fibre is high for a vegetable, more than cabbage (2.5 g) or courgette (1.0 g).

   But those numbers rarely survive to the table.

   The inside of an eggplant is a sponge full of air pockets. Meeting hot oil, the air escapes and oil fills the space. Eggplant is among the most oil-absorbent vegetables there is.

   Cooking	For one 250 g eggplant
   Raw	63 kcal
   Steamed or boiled	63 kcal (almost unchanged)
   Fried in 2 tbsp oil	63 + 240 = about 300 kcal
   Deep-fried	More

   Two tablespoons of oil is 240 kcal — four times the eggplant itself. That is where "eggplant is good for dieting" tends to come apart.

   There are ways to cut the absorption:

   • Salt it, leave it 20 minutes, then squeeze out the water. As the cells lose water the structure collapses, leaving less room for oil
   • Steam or microwave it first, then fry. The air pockets have already collapsed
   • Get the pan properly hot before it goes in. A lukewarm pan just gets drunk dry

   Do not peel it. The purple is nasunin, an anthocyanin, and the fibre concentrates in the skin too. But there is no evidence that nasunin does anything in people — having a pigment and having an effect are different claims.

   Cut surfaces brown. That is polyphenol oxidase; salted water or cooking it straight away limits it.

3. 03Not established

   "Eggplant soaks up oil, so it absorbs and removes cholesterol" — that is not what happens

   This entry sorts through a common misunderstanding.

   You often hear it explained this way: "eggplant soaks up oil like a sponge, so it soaks up the fat and cholesterol inside your body and carries them out."

   This confuses two different things.

   First, what happens in a frying pan is not what happens in your gut. Eggplant absorbs oil in the pan because of its physical structure — liquid filling air pockets. But when you eat that eggplant, you eat the oil it absorbed too. It goes into you, not out of you.

   Second, digestion destroys the structure. After chewing, stomach acid and digestive enzymes, no sponge remains. What reaches the intestine is eggplant's constituents, not an eggplant-shaped sponge.

   Is there nothing that binds fat and bile acids in the gut? There is — soluble fibre. Oat beta-glucan and psyllium lower LDL that way, with evidence behind them.

   But the soluble share of eggplant's 3.0 g of fibre is low next to those foods. And decisively — two clinical trials that fed people eggplant both matched placebo. However plausible a mechanism sounds, if the human result does not appear, that is the end of it.

   The same applies to "nasunin is an antioxidant". Nasunin is the anthocyanin in eggplant skin, and it shows antioxidant activity in a test tube. But this site did not identify evidence that it changes a health outcome in people.

   None of this means you should not eat eggplant. A vegetable with 25 kcal and 3 g of fibre needs no further defence. But that is the benefit of eating vegetables, not a benefit unique to eggplant.

How to eat it well

What to watch out for