Prevent sickness

1. Focus on Vitamin D (but NOT in "fortified" foods or synthetic forms in pills)
 
 
If you get your vitamin D levels tested, you generally want to be between 40-80 ng/ml. Once you get above 50 ng/ml, that's where the real benefits start to happen with a maximized immune system and balanced hormones.

You might be surprised to know that MOST people have low vitamin D levels (especially in the winter), and a lot of people are surprised to find that they could be dangerously low.  Some people I know who thought they were reasonably healthy actually had levels below 20 ng/ml (one friend's level was measured at a shockingly dangerous 11 ng/ml), which is a range that could severely limit your immune system and hormone balance (and explains the frequent colds and hormone problems that they were having).

Personally, I found out that my winter levels a couple years ago were lower than I thought (around 35 ng/ml despite taking cod liver oil a couple times a week) and then after getting a few months of summer sun, my levels had jumped up to 52 ng/ml by the end of July, which is much healthier.  This was without any Vitamin D supplements as I wanted to get a good idea of where my levels stood from just food intake and sunshine as my sources. 
Keep in mind though that I'm an avid hiker and mountain biker in the summer, and I live at high elevation (7500 feet above sea level), so I get a good deal of daily sun, which is why my levels jumped from 35-52 ng/ml after a couple months of daily summer sun.  For people that are in offices daily, you'll still most likely need supplemental Vitamin D3 to keep blood levels of vitamin D from dropping too low.

When it comes to Vitamin D, you need to be careful about artificial forms of vitamin D in many vitamin pills, as artificial vitamin forms are almost always either ineffective or possibly even detrimental compared to natural forms.  Vitamin D2 is generally the artificial version in multi-vitamins, although natural D2 does exist in some foods like mushrooms.  Natural Vitamin D from either cod liver oil and/or an oil-based D3 supplement are the best options in my opinion for the times of the year you're not getting enough sun. 

Personally, this is the oil-based D3 supplement that I take during the winter now and also on days in the summer if I happen to go a few days without any sun.  I alternate this oil-based D3 supplement with a fermented cod liver oil throughout the winter, so that I get good natural vitamin D from various sources.

Keep in mind that it's best to get your vitamin D naturally from the sun if you can.  The sun is the absolute best source of vitamin D, and leads to a powerful strengthening of your immune system when your body can naturally produce Vitamin D from moderate sun exposure.  When the UVB rays (not UVA rays) from mid-day sun hit your skin, it reacts with oils in your skin to produce vitamin D that is slowly adbsorbed by your body.  Note that sunscreens block the ability of your body to produce vitamin D, and most sunscreens also contain carcinogenic chemicals that absorb into your blood stream. 

I know not everybody can take a tropical vacation every winter, but if you can, it's best to try to take it right smack dab in the middle of the winter (when your vitamin D levels have dropped to their lowest)... getting even a few days to a week of good sun closer to the equator in the middle of winter can really help increase your vitamin D levels and strengthen your immune system for at least several weeks after the trip.

Remember that this does NOT mean getting burned in the sun... it means getting a moderate amount of sun on large portions of your body (not just your face) for approx 15-40 minutes per day WITHOUT sunscreen on (since sunscreen blocks the UV rays that directly stimulate the vitamin D production in your body).   Also, as a warning about sunscreens, see this article here about why sunscreens can possibly cause cancer and increase body fat.
Everybody is different based on their skin tone... very pale skin tones may only need 10-15 minutes or so in full sun in the middle of the day to get adequate vitamin D before any skin damage occurs, but darker skin tones may need a slightly longer time (sometimes 40-60 minutes) in the sun to produce adequate vitamin D.  To protect your skin, it's essential to get enough sun without sunscreen on, but NOT get burned. 

In general, the UVB rays are only strongest from about 10 am to 3 pm to trigger Vitamin D production in your body (depending on time of year, latitude, and altitude).  For example, in NY city, while you may be able to produce vitamin D in your skin between 9am to 4pm in June or July, that time frame when UVB rays are strong enough might have shrunk to only 11am to 1pm by the end of September... and by late October in NYC, according to charts of sun height in the sky, you can't produce any vitamin D even in mid-day sun as the sun is too low in the sky and UVB rays too weak.

With that said, I understand that a tropical vacation in the winter is not possible for everybody's schedule based on either work or finances, so...
Since you may not be going on a tropical vacation this winter, how can you still keep Vitamin D levels from falling dangerously low in your body?

Well, the best food sources of natural Vitamin D are egg yolks (from hens fed a healthy diet and allowed to get their own sunshine), fatty fish such as salmon and mackerel, organ meats, and some mushrooms (some portobella mushrooms and maitake mushroom are fairly good sources of vitamin D, although the type of vitamin D in mushrooms might not be the best utilized source in your body).  However, keep in mind that it's tough to get enough vitamin D in the winter from food sources alone.

But what I do to make sure I'm at least getting a decent amount of the best absorbed vitamin D is to take a moderate dose of fermented cod liver oil daily in the winter to make sure my vitamin D levels don't fall too low.  Make sure to take only small to moderate doses of cod liver oil, as large doses can possibly give you an overdose of Vitamin A.  
What I've done lately is to only take cod liver oil about 3 days per week, to prevent taking in too much vitamin A.  On the other 4 days per week (only in the winter), I take an oil-based vitamin D3 supplement. It's important to choose an oil-based D3 supplement as it's better utilized by your body.

I'm also a big fan of Prograde Nutrition's natural VGF-25 multi-vitamin, which derives it's vitamin D from natural fish liver oil instead of a synthetic form of vitamin D.  All of the other vitamins in VGF-25 (which stands for "25 veggies, greens, and fruits") are naturally derived too instead of most multi-vitamins that you find at your corner store that are synthetic.
By the way, fortified milk has added synthetic vitamin D, so it is NOT a good source.  In fact, I don't trust any "fortified" foods at all, including terribly unhealthy breakfast cereals which claim to be good sources of vitamin D... not so!  Also make sure to read this article, which explains how our food supply has been modified in recent decades and now lacks the vitamin D that it used to contain decades ago.

2. Garlic to strengthen your immune system!

Garlic is one of the most potent of all superfoods!  Not only does high dose garlic go back thousands of years for treatment of sickness, but recent studies back up the legendary claims for garlic boosting your immune system.

What's best though -- "aged" garlic pills, whole garlic in foods, capsules, etc?  I can't seem to find a consensus on this one, so what I simply try to do is use a variety of sources, including garlic powder on a lot of my foods, fresh chopped garlic in meals, and also a garlic capsule or two each day.

If I feel a possible cold or sickness coming on, I really start loading garlic into my foods heavily and I take a few extra garlic capsules that day too. 

3. Kombucha tea, Kefir, Fermented foods (and other sources of probiotics) strengthen your immune system

Kombucha tea is a fermented tea (naturally effervescent) that contains billions of friendly gut organisms (probiotics) that help to strengthen your immune system by bolstering your levels of good organisms in your gut, which provides a first level of defense against pathogens from things you ingest.

Remember that 70% of your immune system lies in your gut flora and the health of the friendly organisms in there to protect you against pathogens and sickness.
You can find bottles of Kombucha tea or other probiotic drinks at health food stores such as Whole Foods. 

Kefir is a cultured/fermented dairy drink that's been used for thousands of years as a health elixer in many parts of the world.  Kefir is an even better source of probiotics than Kombucha tea, but keep in mind that variety is best when it comes to probiotics, so use various sources for the best benefits to your digestive system and immune system.  Kefir is also the easiest form of dairy to digest due to the pre-digestion that's done by the probiotic microorganisms, and due to this, kefir is generally 99% lactose free.  Read this article to see why Kefir is a more powerful source of gut-friendly probiotics than yogurt.

When I feel any sickness coming on, I start loading up on Kombucha tea and Kefir, drinking them both throughout the day.  I've started seeing other probiotic drinks on the market recently too, so just make sure to look for one that has very minimal sugar per serving (3-6 grams per 8 oz serving is acceptable, but much more than that is too sugary).  Kevita is one brand of probiotic drink that is really delicious and has minimal sugar, while also containing around 8-10 Billion organisms per bottle I believe.

You can also get beneficial probiotics from fermented foods such as sauerkraut (non-canned), yogurt, kimchi, and other fermented foods.  There are also plenty of probiotic supplements you can take, one of which is a delicious drink called Athletic Greens, which contains 7 Billion probiotics per serving among 76 other superfood ingredients.  I start off every morning with this superfoods drink mixed with fresh squeezed lemon and unsweetened iced tea... Great stuff!

Another probiotic product that I personally take is called Pro-x10 and is one of the most powerful probiotics I've come across yet, with the equivalent of 50 Billion probiotics, and a micro-encapsulation technology that gets more live probiotics to your intestines, so they don't die in your stomach.

4. Green tea, Chamomile Tea, and other teas

There is evidence that green tea and chamomile tea can help aid in strengthening the immune system.

Even if the effect is small, you can't go wrong because both are loaded with powerful antioxidants unique to each tea.

For that reason, I try to drink a couple cups of green tea with a small bit of raw honey early in the day, and then at night, I have a couple cups of chamomile or mint tea.
This isn't a bad idea even for a regular habit, but it's even more important when you feel a sickness possibly coming on.  I also drink a lot of other teas too such as Rooibos tea, which is thought to be even higher in antioxidants than green tea.
  5. Loading up on antioxidants

We already know how important antioxidants are to overall health as well as immune system support.
For this reason, I make sure to really load up on antioxidant-rich fruits, berries, teas, red wine, unsweetened organic cocoa (in smoothies, etc), and veggies to help prevent sickness.
Sometimes I make what I call my "Superhuman smoothie", which I believe can really bolster your immune system, with loads of powerful antioxidant-rich berries, a few veggies, raw cacao, maca, spirulina, chia seeds, and any other superfoods I can think to throw in there.
 
6. Light exercise (yes - light exercise, not hard)

When you feel a sickness coming on, a super-high intensity workout is not a good idea, as hard training forces the body to do a lot of recovery, this at a time when your body needs all of it's efforts on trying to fight off the oncoming sickness.

Although I usually recommend high intensity training most times... when sickness might be coming on, it's just a good idea to get some light exercise instead.

Personally, I like to get outside for some fresh air and go for a hike or go snowshoeing in the winter. These aren't very strenuous for me, so they won't cause my body to be forced to do a lot of recovery... but just getting out in the fresh air and getting the circulation going I feel is good to help the body fight off the sickness.

7. Avoid ALL processed foods, wheat-based foods, and sweetened soft drinks

If you're serious about your health and getting lean for life, this should be an everyday rule for you anyway (except maybe for cheat meals)...

However, when you might have a sickness coming on, this is no time to bombard your body with processed foods, inflammatory omega-6 oils (soybean oil, corn oil, etc), fried foods, high fructose corn syrup, refined sugars, wheat-based foods or chemical additives.
All of these force your body to do extra work to deal with all of this junk and the internal inflammation that they cause in your body.  And by the way, grain-based foods like bread, cereal, muffins, pasta, and bagels are a big culprit in causing internal inflammation and disrupting normal gut function, so avoid grains as much as possible.  In case you're new to the science of Paleolithic nutrition, humans don't actually need grains to survive...grains were never a part of the ancient human diet until agriculture came around only about ten thousand years ago. If you haven't seen this article yet, here are 11 reasons why whole wheat damages your body.

Instead, (especially when you might be getting sick) you need to give your body only wholesome unprocessed foods that are only 1 ingredient and that we were meant to digest most efficiently...fruits, berries, veggies, eggs, nuts, seeds, grass-fed meats, etc.

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