Posted by Larry Hoover on November 26, 2002, at 9:08:41
In reply to Hempseed oil? » Larry Hoover, posted by viridis on November 26, 2002, at 5:02:16
> Hi Larry,
> Since we're picking your brains on lipid metabolism (and you seem very knowledgeable), could you offer a brief synopsis/opinion on hempseed oil (and pumpkinseed oil too, if possible)?
> Thanks in advance,
Hemp oil has a good fatty acid balance, I suppose, but only in comparison with other vegetable oils. It might be rather unique in being a source for both isomers of 18:3 linolenic acid. Still, it falls short of the target of 1:1 ratio of omega-6:omega-3. I've heard it said that hemp is also a source of EPA, but that is not correct; the 20 carbon fatty acid is a mono-ene, and is not interconvertable with EPA. It's in low concentration, in any case.
gamma-Linolenic acid (18:3 omega-6) 3.10%
alpha-Linolenic acid (18:3 omega-3) 20.00%
Eicosaenoic acid (20:1) 0.50%
Data on pumpkinseed oil is harder to find. It's main claim to fame, I suppose, is its high linoleic acid content (50-60%). Linoleic acid is an 18:2 omega-6 (please note the confusing similarity of the name with linolenic acid, which is 18:3). Linoleic acid has the dubious merit of being considered to be an essential fatty acid. It was merely the first to be identified, and some still say the only such fatty acid. Despite the burgeoning evidence of the essentiality of omega-3 fatty acids, some still cling to this old concept. With the huge amount of vegetable oils being consumed today, there is a virtual zero per cent likelihood that anyone needs more 18:2 linoleic than they're already getting. There's very little of the higher polyunsaturates to consider, so I don't see anything in any way special about pumpkinseed oil. Pumpkin seeds, however, are a different matter. They're quite nutritious.
total PUFAs (not linoleic): <2%
The take-home message is that I don't see anything particularly special about these oils, but hemp has a better profile. Cold-pressed oils may contain other fat-soluble materials like phytoestrogens (e.g. beta-sitosterol), but that's another story.