Does black seed oil work as a supplement?
Black seed oil has shown measurable effects on blood fats, blood pressure and inflammatory markers in multiple meta-analyses, but a clear dosing recommendation is lacking and interactions with medications are a genuine point of concern.
Black seed oil works: multiple meta-analyses of placebo-controlled studies show measurable effects on blood fats, blood pressure and inflammatory markers.
The evidence is strongest for blood fats. An analysis of 34 studies involving more than 2,200 participants showed significant reductions in LDL cholesterol, total cholesterol and triglycerides, while beneficial HDL cholesterol rose. Whether this also leads to fewer heart attacks has not been studied. If you take medication for your cholesterol or have cardiovascular problems, discuss this with your doctor. On the label it is listed as 'Nigella sativa', either as an oil (in capsules or liquid form) or as a powder in capsules. The studies do not show which form works better. Studies used doses ranging from 200 to 4,600 mg per day over 1 to 48 weeks, but no clear recommendation can be distilled from them.
For weight loss, 13 studies involving 875 participants showed an average reduction of 1.76 kg and a small drop in BMI. Waist circumference did not decrease significantly. Do not expect a powerful slimming supplement. Here too, 200 to 4,600 mg per day was the range used in the studies, with no single optimal dose emerging.
For blood sugar in diabetes and for blood pressure it appears promising, but the evidence is less conclusive. In research, participants received doses within the range of 200 to 4,600 mg per day. Discuss this with your doctor before combining it with your medication. For antioxidant effects alone, liver and kidney protection, cancer, infections or brain protection, the evidence is too thin or comes only from animal studies: in those cases it is not worth your money; for inflammatory markers there are positive results from human studies, but hard clinical endpoints are lacking. Also be aware of interactions with medications and of the large quality differences between products on the market.
Evidence is based on multiple meta-analyses and systematic reviews of randomised studies. The largest meta-analysis covers 82 RCTs and more than 5,000 participants. Limitations include large heterogeneity (I2 up to 97.8%), varying doses and product compositions, and possible publication bias at large effect sizes.
Do omega-3 (fish oil) supplements benefit my heart?
Fish oil reliably lowers triglycerides and can slightly reduce the risk of a heart attack in people with existing heart disease or high risk, but it does not demonstrably lower the overall risk of death. Always discuss its use with your doctor if you have a condition or are on medication.
How healthy is olive oil and what is it good for?
Olive oil, and extra-virgin olive oil in particular, is well supported as protective for the heart and blood vessels, especially when used in place of butter and as part of a varied, plant-based diet.
Does losing weight noticeably improve my blood pressure and cholesterol?
Losing weight noticeably lowers your blood pressure and improves your cholesterol profile, but which value improves the most depends on your diet. And if the weight comes back, most of the gains disappear along with it.
Is green tea really as healthy as they say?
Two to three cups of green tea a day fits well into a healthy lifestyle and is probably safe, but do not take concentrated green tea extracts as a supplement: they can damage your liver.
Does garlic help against high blood pressure or high cholesterol?
Garlic supplements measurably lower blood pressure in people with hypertension and have a modest favourable effect on cholesterol. They are not a replacement for medication, but can be a worthwhile addition in cases of mildly elevated levels.
Does taking omega-3 help you stay healthy for longer?
Omega-3 reliably lowers your blood fats, but the evidence that it makes you live longer or healthier is limited. If you already have heart disease, discuss with your doctor whether omega-3 is worthwhile as a supplement to your treatment.