Tomatoes, a good source of Lycopene. Spicy peppers boost your metabolism. Goji berries are a new super-food. What do these three foods have in common? They're all part of the Nightshade familiy of vegetables, along with eggplants, bell peppers, potatoes, and gooseberries.

But what exactly is a nightshade anyway? Nightshades are any plant from the family Solanaceae. We are namely interested in two genera: Capsicum and Solanum, or the pepper genus and tomato/eggplant/potato genus respectively. It should also be noted that another genus, Nicotiana (tobacco), is in the nightshade family.

Did You Say Tobacco?

Yes, I most certainly did say tobacco. Those wonderful peppers and tomatoes that you eat are from the same family as the tobacco in the cigarettes that you hopefully don't smoke. So to start things off, let's make a note that all food nightshades contain some level of nicotine, which may also explain why they are so darned addictive.

Dr. Garrett Smith wrote five articles in The Performance Menu: Journal of Health and Athletic Excellence (Issues 33, 35, 36, 37, and 40) detailing exactly how the nightshades adversely affect human physiology.

So What Problems Do They Cause?

Tomatoes and eggplants were originally used as ornamentals rather than as food as they were considered poisonous. One of the major problems attributed to nightshades is arthritis, a disease which affects most of the population at some point in their life. In his first article, Dr. Smith went through an impressive list of animal studies showing calcinosis (the animal version of osteoarthritis) in rats, sheep, rabbits, chicks, and guinea pigs. They aren't humans, but it is multiple mammalian species undergoing the same process.

Remember the nicotine that we discussed above? Studies show that dietary nicotine can inhibit wound healing with anything above extremely small doses. That's not a good thing.

And when we look at the hot peppers, like jalapenos and habaneros, we come to another intersting point. These peppers are the only food we eat that cause us physical pain. Pain is usually interpreted as a bad thing, typically given off by the body as a warning. It also gives some insight into the rather, umm, explosive effects of peppers after their digestion. The body is moving quickly to get them out of the system.

But Capsaicin Is Healthful, Right?

That's debatable. Capsaicin appears to have some inhibitory effects on the healing process as well. Combine capsaicin from the peppers with the small dose of nicotine that comes from eating them and you can see how the healing process can be slowed. Capsaicin can actually be toxic in high doses and inhibits a part of the immune system that hunts down cancerous cells for up to 90 days! Epidemiological evidence shows that cultures that eat high amounts of peppers and tomatoes have higher incidences of cancers all throughout the digestive tract.

That's The Most Ridiculous Thing I've Heard. Of Course Those Vegetables Are Good For You

Oh? Well how about a bit of personal experience. When I first changed my eating habits for the better a few years back, I started incorporating lots of salads (still do, but that's beside the point). One to two salads per day, each with tomatoes and green peppers. Along with that, I was just learning to cook and wasn't a big fan of vegetables yet, so I was dousing them and meat with lots of hot sauce.

As you can see, I was incorporating lots of nightshades into my diet. At that level of consumption, I started getting all kinds of popping in my joints, especially in my back and even in my sternum. It wasn't painful, but that I could pop pretty much anything at will was disconcerting. At the time I had no idea about nightshades, so I just kept munching along with no idea of the cause, figuring that since there wasn't any pain, it was benign.

Later, I read some of Dr. Smith's ideas about nightshades and I decided to try cutting back. I cut out the tomatoes and peppers from my salads and cut back on the hot sauce. Would you believe that the popping in my back and sternum went away? It did.

But here's the fun part...I had shoulder surgery last June after two more dislocations. Now that I have "a bum stick," I also have a gauge of whether I've overdone it on the nightshades. Since the nightshade vegetables tend to promote joint inflammation, I can feel it acutely in my left shoulder joint, particularly when exercising, but there will also be a constant dull ache. It feels like I have small air or fluid pockets under the ball of the humerus. And one week, light exercise will irritate it if I've been overdoing the nightshades, while the next I can do max deadlifts, squats (puts the shoulder in a tight position), presses, or anything else with no intra-joint pain if I've been laying off the nightshades. That's all the proof I need.

So I Should Avoid All Nightshades?

Of course, I'm not bold enough to say that, without a doubt, nightshades are bad for everyone. However, I will say that everyone should try going a month without them to see if it has any effect on how they recover from exercise, how their arthritis feels, and how they feel in general. Then, go bananas and have a nightshade festival. Eat nightshades to your heart's content and see how you feel for the next few days. Try incorporating plenty of potatoes, tomatoes, peppers, and spice in your meal. I have a feeling that these foods affect everyone to some degree. I know that I can include a little with no ill effects, but need to watch overdoing it. I'm working to completely exclude them from my diet.

In the end, experimenting on yourself is really the only way to know what does and doesn't affect you. One thing the information on nightshades reinforces for me is to eat seasonally. These vegetables are only available during certain months of the year if eating seasonally, which means that you'll get a good load of nightshades at some points and none at other points of the year.

Another source of information is the Arthritis Nightshades Research Foundation. It's all very unfortunate since a fresh-made salsa could be one of nature's greatest gifts to man. But besides the obvious foods like tomato sauce and salsa, you also have to watch for paprika (made from dried peppers), which is in most prepared mustards, many seasoning rubs, and the seasoning mixes of pre-made sausages and bacon. It can get tough with store-bought foods. I'm not telling you what to eat and what not to, but I am saying to give it some consideration and try an elimination on yourself.