When Baker et al. quietly published a gender-based difference in the concentration of lyso-phosphatidic acid (lyso-PA) in 2001 , it wasn’t taken all that seriously. This was partly because the methods they used for both isolating the lipid fraction and for profiling it were not conventional, and partly because it was quite a narrow result in the grander scheme of things. However, recent work by Sales et al.  might just be enough to broaden this observation. Sales et al. found that not only is there probably about a 10% natural variation in the lipid profile in healthy individuals, but that the profile of both lipids and fats is related to gender, the use of hormonal contraceptives and personal disposition.
Sales et al. report that there is a statistically significant difference in the blood plasma concentration of several lipids. This includes similar lyso-lipids to the lyso-PA targeted in the Baker study, but also larger fraction, mainstream lipids such as PC, PE, PI and sphingomyelin (SM) in healthy men and women in their 20s.
The differences between healthy women taking hormonal contraceptives and those who do not also appear to be significant, and they are also significantly different to the men. At first sight, the variation within each group is wider than the variation between groups, but student t-tests indicate that the likelihood of the difference in absolute values being down to chance is less than 5%, indicating a significant difference.
There is also evidence that the concentration of certain glycerides, including fats, is partly gender- and hormonal-contraceptive-dependent, with members of the latter group having higher triglyceride concentration than women who do not take hormonal contraceptives. This may have implications for treating illnesses related to lipoproteins, though further work is required to determine whether gender or hormonal contraceptives have a significant role in this.
This work is interesting enough on its own, but it comes shortly after another study, by Aviram et al., that showed that lipid distribution in certain parts of cells varies during the day  and a third, by Dawaliby et al. that showed that a lipid called PE is an important regulator of membrane fluidity in eukaryotic cells . These studies between them show that the concentration of major structural lipids such as PE and PC vary throughout the day and are dependent on your gender and the pills you take.
These studies are juicy for lipid researchers because they support notions that lipid geeks like me have worked with for some time. For example, that the lipids we require for our cells to function are a dynamic and responsive group of molecules that we have yet to fully understand.
This work also raises a variety of questions. Are other factors important, like diet, temperature, the seasons etc.? What about the difference between the healthy systems studied and metabolic diseases? The list goes on. It also hints that lipids are under-rated parts of our cells that might be able to give away more information than we think.
1. D. L. Baker, D. M. Desiderio, D. D. Miller, B. Tolley and G. J. Tigyi, Analytical Biochemistry, 2001, 292, 287-295. 10.1006/abio.2001.5063.
2. S. Sales, J. Graessler, S. Ciucci, R. Al-Atrib, T. Vihervaara, K. Schuhmann, D. Kauhanen, M. Sysi-Aho, S. R. Bornstein, M. Bickle, C. V. Cannistraci, K. Ekroos and A. Shevchenko, Scientific Reports, 2016, 6, 27710. 10.1038/srep27710.
3. R. Aviram, G. Manella, N. Kopelman, A. Neufeld-Cohen, Z. Zwighaft, M. Elimelech, Y. Adamovich, M. Golik, C. Wang, X. Han and G. Asher, Molecular Cell, 2016, 62, 636-648. 10.1016/j.molcel.2016.04.002.
4. R. Dawaliby, C. Trubbia, C. Delporte, C. Noyon, J.-M. Ruysschaert, P. Van Antwerpen and C. Govaerts, Journal of Biological Chemistry, 2016, 291, 3658-3667. 10.1074/jbc.M115.706523.