I’ve heard that one of the theories scientists have put forth to explain the increase in asthma and allergy rates is called the “hygiene hypothesis.” What is the hygiene hypothesis, and how does it work?
Our immune systems were designed to cope with a germy world. Unless you live on a farm, postindustrial life can be relatively sterile. Theoretically, exposure to microbes and parasitic worms early in life matures the immune system, priming it to fight microbes rather than such innocuous things as pollen and dander. According to the hygiene hypothesis, a lack of exposure tips the immune system toward inflammation and allergic tendencies, as does the use of antibiotics in the first year of life. In addition, children born by caesarean section face a higher risk of allergies and asthma, because passage through the birth canal inoculates infants with bacteria that normally populate skin, the upper respiratory tract, guts and other organs. The development of healthy gut bacteria positively shapes the immune system.
Proponents of the hypothesis point out that kids who attend day care early in life, grow up in larger families, or spend time around barnyard animals (or at least dogs) are less likely to develop asthma, hay fever and eczema. Critics of the hygiene hypothesis respond that asthma rates have also soared in recent years among children in cities, who may also be exposed to different kinds of dirt and germs. Other possible factors contributing to higher allergy rates in the United States include increased consumption of junk food, inactivity and obesity.
We can all agree on the benefits of clean drinking water and modern sanitation methods. Meanwhile, here’s how you can expose yourself and your family to reasonable levels of germs: Spend time outdoors. Garden. Play with a dog. Afterward, wash up with plain soap and water. If you already have asthma aggravated by dust mites, reduce symptoms by keeping a clean house and enclosing pillows and mattresses in airtight covers.
Photo by Fotolia/Diana Taliun: Children who keep company with furry friends are less likely to develop asthma and eczema.
How often should I swap out my furnace filter, and which types of furnace filters are best?
A furnace filter removes dust, dander and other large particulates from the air in our homes when either the furnace or central air conditioner is running, as the two systems share common ductwork for air distribution. Particulate buildup reduces a filter’s effectiveness and makes the fan work harder, shortening its life span. Both the furnace and air conditioner will operate less efficiently and may require more frequent servicing if the filter is too clogged.
The frequency at which you should change your furnace filter depends on the number of people who live in the home; how many furry pets reside indoors; the presence of smoke from tobacco, woodstoves or other sources; how dusty the environment is; the type of furnace filter; and the thickness of the filter.
If you have multiple fur-shedding pets, you live along a dusty road, or several smokers live in the residence, count on changing a 1-inch or 2-inch air filter every month. You’ll likely need to replace a 4-inch filter every two months and a 5-inch filter every three months.
If you have one pet, your home experiences only moderate dust accumulation, or no more than one smoker lives in the residence, filter replacement can shift to two, four and six months, respectively.
If the air in your home is mostly free of dust and completely free of pet dander and smoke, you can replace your filter just once per year.
Some filters are more efficient at filtering air than others. My advice is to buy washable furnace filters that offer the highest level of filtration. Make certain the filter fits exactly. Be sure to post a note on your calendar to remind yourself of how often to change furnace filters in your home. Check your filter every month for the first year after installation. If you find that your filter gets dirty faster than you anticipated, plan to replace it more often in the future.
Photo by Dreamstime/Luckydoor: Keep the air you breathe free of debris by regularly replacing filters.
I want to start my own vegetable seedlings this year. Will I need special light bulbs?
Suitable supplemental lighting is better for starting seeds than the light coming through most windows would be. A setup of lights will allow you to grow a much wider range of vegetable varieties, which will make your garden even more interesting and fun. Until recently, most seed starters used inexpensive fluorescent T12 shop lights, with the height of the lights adjusted so the plants were very close to the bulbs — within a half-inch for full-sun plants, such as tomatoes and peppers.
But two new and better choices, T8 and T5 bulbs, are now available. In fluorescent-light lingo, the “T” stands for “tube,” and the number represents the bulb’s diameter. Old-line T12 fluorescent bulbs are still cheap and easy to find, but for a few dollars more per bulb, you could upgrade to more slender T8 bulbs, which are up to 40 percent more efficient. Plants get plenty of light when grown within 2 inches beneath T8 bulbs. You can usually find a 4-foot-long, Energy Star-certified, two-bulb T8 fixture at retail stores for about $20, plus another $10 for the bulbs.
Many garden-supply stores now offer grow lights that use even skinnier T5 bulbs, sometimes called “high output” (HO) fluorescents. Less glass is required in their manufacturing, and T5 bulbs are 9 percent more efficient than T8 bulbs and 51 percent more efficient than the old T12s. While T5s are some of the best grow lights for starting seeds indoors, as they set the standard for light output and energy efficiency, they may be glaringly bright if not equipped with a reflective hood. Plant height must be closely monitored, too, with no less than 3 inches of space between the bulbs and the tops of the plants. Some people find the narrow T5 bulbs too delicate to handle in 4-foot lengths, and instead choose shorter, 2-foot bulbs.
For more information on growing your own vegetable seedlings, see Best Tips for Starting Seeds Indoors.
Photo by Jerry Pavia: Sprouting seeds will flourish beneath bright, efficient fluorescent bulbs.
Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.
I often hear that I need to eat antioxidant-rich foods. What are antioxidants, and how do they work?
Antioxidant molecules in our bodies inhibit the oxidation of other molecules and neutralize “free radicals,” or unstable compounds. Free radicals are created by oxidation, a chemical reaction involving the loss of electrons in a molecule. More familiar examples of oxidation are butter going rancid, iron rusting, apple slices browning and fires burning. Apply antioxidant-rich lemon juice to your sliced apple, and what happens? The flesh will resist browning.
Free radicals accelerate aging and contribute to many chronic illnesses, including Alzheimer’s disease, arthritis, atherosclerosis, cancer, cardiovascular disease, cataracts and diabetes. To stabilize themselves, free radicals snatch electrons from other atoms or molecules, which can then spark a chain reaction of electron raiding.
While the body’s free-radical production is normal and sometimes even useful, an overload of oxidation can damage molecules, such as DNA, fats and proteins, thereby disrupting cell functions. In addition, oxidation stirs up inflammation, which generates more free radicals.
Other conditions heighten free-radical formation and oxidative stress: tobacco smoke, certain forms of pollution, fever, infection, chronic inflammation, chronically elevated blood glucose (diabetes), ultraviolet light and radiation, extreme exercise, and consumption of unhealthy hydrogenated fats, such as trans fats and oils in fried foods.
Many normal bodily processes create free radicals, such as when our bodies break down nutrients for energy, fight off infection or detoxify drugs. But the body also produces its own antioxidants to neutralize free radicals — a process that works well until an excess of free radicals overwhelms the system.
Eating antioxidant-rich foods can restore the balance. Animal products contain some antioxidants, but your richest sources are plants, which contain antioxidants such as vitamin C, vitamin E, selenium, carotenoids and flavonoids.
Carotenoids and flavonoids double as plant pigments, so eat a variety of colorful fruits and vegetables, as well as culinary herbs and spices, to maximize your dietary antioxidants. Particularly rich sources include berries, cherries, red grapes, papaya, pumpkin, carrots, green tea, garlic and cruciferous vegetables, such as broccoli, cabbage and kale.
Now that you know how antioxidants work in your body, learn more about building a diet around them by reading The Best Antioxidant-Rich Foods for a Disease-Fighting Diet.
Photo by Dreamstime/Maffboy: Eat your colors! Vividly hued foods, such as these bright berries, are rich in antioxidants.
What’s the best way to replace wooden tool handles? I’ve got an axe with a handle that’s completely broken off, and a sledge hammer with a cracked handle.
Hammers, hatchets, axes and sledge hammers usually have wooden handles and eventually they all get loose and break in time. That’s why learning to replace wooden tool handles is such a useful self-reliance skill. You really can’t pay anyone to do this work for you, and you shouldn’t.
Get a new handle, whittle it to fit your tool head, then anchor the handle into the head so it doesn’t move. These are the three steps to tool handle replacement, but you’ll need to understand details for success.
Hardware stores everywhere sell replacement wooden handles, but when you select one, look for growth rings that extend from the front of the handle edge to the back. Avoid side-to-side grain orientation since this makes for a weaker handle. Grain orientation is not something that tool handle makers pay attention to, so you’ll find a wide variety of growth ring patterns on any store shelf.
What you might not realize is how easy it is to make a handle from scratch. Easier and better than buying because you have more control over wood quality. Why pay for a replacement handle that’s weaker than something you can make in less time than it takes to travel to the store?
I was reminded of all this last week when I made a new 18” long wooden handle for one of my 4 lbs. stone hammers. The whole job took less than 45 minutes from rough lumber to installed handle, and the process of making a new handle begins with a table saw.
Where my homestead is on Manitoulin Island, Canada, ash is the wood of choice for tool handles, but hickory is even better if it grows where you live. Either way, cut a piece of wood that’s as wide and as thick as it needs to be to fill the hole in the head of the axe or hammer you’re making the handle for. As you work, keep that all-important growth ring orientation in mind.
After using your table saw to cut your handle blank to thickness and width, tilt the blade over 45º to saw off the corners of the handle blank. Bringing it closer to an oval shape on the saw means less work to do next with the spokeshave.
Any simple vise works for holding your handle blank while you shape it. Keep an eye on the old handle if it’s around and let it guide you as you shape the new one.
Fitting a new handle to the tool head is the same whether you make your own handle or buy one ready-made. For a detailed, illustrated lesson on the process, download my free, full-color report How To Replace Wooden Tool Handles.
Photo by Steve Maxwell
Steve Maxwell and his family have homesteaded on Manitoulin Island since 1985. You can visit Steve’s homestead online at his Real Rural Life blog.
How should I choose a router table? I’m planning to make trim and molding for a renovation at my house, but I really don’t know where to start when selecting a router table. There are so many to choose from, and the cost varies a lot. Can I make my own?
A router table is one of the most useful additions to any home workshop because it boosts safety and usefulness. There are many different kinds of router tables, but all work on the same idea. Instead of being used free-hand, the router is mounted upside down in the router table. You move the wood over the router instead of the router over the wood.
When I first started woodworking seriously in the early 1980s, you had to make your own router table to find a decent one, but that’s changed. Making your own table is still a great idea, but if you’d rather spend a little more money and a little less time getting to your woodworking projects sooner, there are lots of options for a purchased table.
One way to learn about router tables is to see what I use in my own shop. Check out my router table screencast:
Photo by Steve Maxwell
Steve Maxwell and his family have homesteaded on Manitoulin Island since 1985. You can visit Steve’s homestead online at Real Rural Life.
I found some old cast-iron cookware that’s rusty and covered in black crud. Can I resurrect it?
Old cast iron can be a bargain, says Mark Kelly, public relations manager for Lodge Manufacturing in South Pittsburg, Tenn., the last U.S. manufacturer to cast its own iron. Kelly says cast-iron cookware from China is usually lower-quality, with several telltale signatures: It will have odd marks at the “throat” of the handle and perhaps on the bottom, it may not look as finished, it will be thicker and clunkier, and the edges won’t be as smooth. A better bet would be a piece of U.S.-made cookware, no matter how gunky it may appear.
If you’ve found a well-made cast-iron piece, restoring it will be fairly easy. Kelly instructs: First remove rust using a soap-free steel wool pad (or have the rust sandblasted off at a metal shop), and then bake away any crust by heating the piece on a grill, over a wood fire, or in your self-cleaning oven. Cleaning it outside may be best, because the process could otherwise fill your house with smoke. You may need to repeat this process several times before the crust is gone.
When the cast iron is clean, re-season it by applying the cooking oil of your choice all over it. Preheat your oven to 350 degrees Fahrenheit, and bake the piece upside down for an hour. Don't line your oven floor with aluminum foil, as it can melt and fuse to the bottom of some types of ovens. Instead, if you need something to catch drips, use a cookie sheet placed below the cast iron. After an hour, turn off the oven and let the piece cool.
Seasoning cast-iron cookware fills the pores of the metal with carbon particles, which creates the nonstick effect, Kelly says. The more you cook with the piece, the more that effect will be enhanced, and that’s why it gets better with time. Re-oil the piece after each use.
“There’s no way to ruin cast iron,” Kelly says. “Well, in Leviticus, it does say that it’s a straight path to hell if you put cast iron in your dishwasher. But that’s the only way.”
To learn more about caring for cast-iron cookware, read The Care and Feeding of Cast Iron: Cleaning and Seasoning Cast-Iron Cookware.
Photo by Fotolia/Jaimie Duplass: Salvage crusty cast-iron with a bit of scrubbing and baking.
Robin Mather is a senior associate editor at MOTHER EARTH NEWS and the author of The Feast Nearby, a collection of essays and recipes from her year of eating locally on $40 a week. In her spare time, she is a hand-spinner, knitter, weaver, homebrewer, cheese maker and avid cook who cures her own bacon. Find her on Twitter, Facebook or Google+.