One of the guys on The Peak Testosterone Forum essentially asked the question, "Why would any man take flaxseed?" I would actually ask it the other way around: why would any man NOT consume flaxseed? Flaxseed is that good and arguably the most powerful superfood on the planet right now. (One could make a great case for spinach, broccoli and berries however.) I simply do not know any food that can do as much for men as flaxseed. As you'll see below, it does literally everything a guy could possibly want a food to do, including clear benefits for the bedroom.
Tragically, it is currently in vogue to attack plant foods (at least here in the U.S.). Flaxseed comes under fire from those who have not bothered to read the research, because it has a fairly high phytoestrogen content. In fact, it is obvious that the above poster had read material from these blogs:
"Okay guys, Cronos, Peak T, anyone... sort me out with a quick answer, you're all well informed on here. Remind me again...why should we be taking flaxseed oil or flaxseed in general, when we know it to be a 'gazillion' times more estrogenic to the male body than (processed) soy? Thank you..." 
However, I have challenged him and the other men on The Peak Testosterone Forum to name even ONE estrogenic symptom associated with flaxseed consumption. I know of no credible source that says it lowers libido, lowers testosterone, raises estradiol, makes a man moody, etc. It just doesn't happen and the benefits are, in contrast, overwhleming. In fact, as you'll see below, flaxseed is incredibly protective of your bedroom activities: it will help keep you in the game decade after decade.
Think I'm exaggerating? Check out these bedroom and general health benefits below:
1. Protecting Against and Possibly Clearing Out Penile Arterial Plaque. I know of only one other food - Pomegranate Juice - that has research showing that it can single-handedly help with arterial plaque. However, we have another recent addition to the family: flaxseed. (See my page on Pomegranate Juice: Your Best Bedroom Buddy for more details on this powerhouse.) For example, an animal study showed greatly decreased plaque progession in flaxseed fed animals versus controls:
"Dietary flax-supplementation resulted in a significant â‰ˆ40% reduction in plaque formation (P = 0.033). Both Group II and III animals displayed improved contraction and endothelial-dependent vessel relaxation. Dietary flaxseed is a valuable strategy to accelerate the regression of atherosclerotic plaques; however, the flaxseed intervention did not demonstrate a clear beneficial effect on vessel contractile response and endothelial-dependent vasorelaxation." 
Will it actually help you regress the plaque you already have? My guess is 'yes' - and you'll see later why I say this - but suffice it to say that flaxseed has many CVD marker and atheroclerotic studies under its belt. And keep in mind that almost every man growing up with a Western lifestyle has signficant plaque if they are over the age of about 30 - sometimes younger! - and so flaxseed is clearly a fantastic tool in their arsenal. Also remember that it only takes a little bit of plaque in your penile arteries to really make a difference in erectile strength.
2. Powerfully Lowering Blood Pressure. Many men have hypertension and the added pressure on arterial walls is a risk factor for erectile dysfunction and atherosclerosis (and stroke, etc.). Many men do not realize that a recent study showed that flaxseed lowered blood pressure in a study on men and women with hypertension by an average of 15 points (mm) systolic and 7 points (mm) diastolic.  This is a huge drop and rivals that of most of the phamaceutical solutions out there! Now the study in #1 did not show a signficant increase in endothelial function. However, this will undoubtedly occur in most of those with high blood pressure per the above
3. Protecting You From Prostate Cancer. I point out everwhere I can that research shows that about half of all men by middle age have small prostate cancer nodules growing within their prostate. Now this is no reason to panic, because prostate cancer typically grows slowly. But, given the right environment, those nodules can grow and raise your PSA value. Then the ugly stuff starts to happen:
a) Your urologist may want to biopsy you. This means a painkilling shot into where the sun don't shine and ejaculating blood for a few weeks while your prostate heals from the samples they clipped out of it.
b) If you are on HRT, you will probably be pulled off of HRT while you are evaluated with a biopsy. See my story High PSA But No Cancer for a very personal example of this.
c) Unfortunately, these nodules can metastisize. Once this happens, it is very hard to treat and, well, you know the story.
So where does flaxseed come in? Well, it currently has the best research to date showing that it can actually partially reverse prostate cancer. This is remarkable if you stop to think about, i.e. the fact that one food can actually make a difference against malignant cells within your body whose sole purpose is to violently grow and feed off of your tissues. I discuss all the recent research in my page called Flaxseed and Prostate Cancer. Again, considering that so many men in Western societies probably have the roots of prostate cancer already, to me it is a no brainer.
And, by the way, try to have an active sex life after you've had a biopsy and your wife or girlfriend is worried over your rising PSA and if you're gonna be there next Christmas...
4. Decreases in LDL, Triglycerides and Lp(a)l. Many studies have shown flaxseed's incredible ability to lower cardiovascular disease markers. Again, flaxseed potency in this arena is similar to Pomegranate Juice in terms of it's sweeping potency and long term arterial protective powers. I plan on doing a more detailed page on the subject, but let's just look at the conclusions of one study here (on men and women with high cholesterol):
"Flaxseed supplementation was associated with significant reductions in TC (-17.2%), LDL-C (-3.9%), TG (-36.3%) and TC/HDL-C ratio (-33.5%). There were no significant differences in absolute change in BMI nor in percentage change in TC, HDL-C, LDL-C, TC/HDL-C ratio between flaxseed and statin groups. Dietary flaxseed significantly improves lipid profile in hyperlipidemic patients and may favorably modify cardiovascular risk factors." 
First of all, notice that the authors compared its powers to the pharmaceutical statins. And notice that it powerfully dropped triglycerides and total cholesterol (and its modest reduction LDL). If you've read my page on How to Clear Your Arteries of Plaque or my page on HDL, LDL and Triglycerides, then you've got some starter info as to how these markers can reasonably reliably help you actually regress plaque (or maintain zero plaque if you are one of the "lucky" individuals). Another study (on women) shows that flaxseed can reduce Lp(a).  This is another risk factor for arterial plaque and it can bite people with good lipid numbers otherwise.
5. Improving Your Omega-3/Omega-6 Ratio. Many of you know that some of our standard plant-based oils, such as sunflower, are high in omega-6's and can lead to inflammation. Flaxseed is completely different, however, as it is packed with alpha-linolenic acid, which your body converts into the all-important omega-3's DHA and EPA. Many guys feel noticably better when consuming flaxseed and this is probably the reason why. Our bodies were meant to consume a very low omega-6 to omega-3 ratio - Dr. Greger says 4:1 is probably the safe maximum - and flaxseed can help you greatly improve this ratio.
Vegetarians and vegans - and I am 95% plus vegan - interestingly enough, get themselves quite frequently into trouble with their omega-6 to omega-3 ratio. The reason? It is probably because in the U.S. there are now so many packaged and processed plant-based foods. Cooking and food preparation is a lot of work and even the health-conscious can be foiled by food manufacturers who, quite frankly, are thinking of convenience, price and shelf-life before the health of their customers.
1) Am J Physiol Heart Circ Physiol (April 12, 2013), "The Effects of Dietary Flaxseed on Atherosclerotic Plaque"
3) Revista Medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi, 2005, 109(3):502-506, "Flaxseed supplementation in hyperlipidemic patients"
4) Nutrition Research, Jul 1998, 18(7):1203â€“1214, "Whole flaxseed consumption lowers serum LDL-cholesterol and lipoprotein(a) concentrations in postmenopausal women"