Category Archives: Food - Page 15

About Green Tea

Posted by on January 30, 2011 77 comments

Erich asked what kind of tea we drink. Tea is a subject dear to our hearts, so we thought we’d discuss it today.

First, some background. Over at Planet Tea they have a useful flowchart describing how different kinds of tea are made:

The critical step is fermentation, which oxidizes the leaf and turns it black. Green tea is unfermented; oolong (wu long) is partially fermented; and black tea (in Asia, “red tea”) is highly fermented. Black tea has a longer shelf life than green tea.

Growing region matters. Mainland China is by far the world’s largest producer of tea, but China is extremely polluted and we would not trust Chinese tea. Japan and Taiwan both produce excellent green teas; we drink tea from both countries.

Taiwanese Tea

The Taiwanese teas with the highest reputation are “high mountain tea”; these are grown at high altitudes above the smog. We drink both green and oolong high mountain teas from Taiwan. Ours come in 300 g vacuum-packed packages:

The one on the left is green tea, the one on the right an oolong; both are “high mountain” teas. Each package weighs 300 g. We use about 4 g (20 leaves) of tea per day, and so a package lasts about 3 months. A single 300 g package of high quality tea may cost $100, so the total cost is about $1 per day; but multiple cups of tea may be obtained from each day’s tea.

The leaves are rolled and dried during processing, and shrivel to a very small size, then re-expand when placed in warm water. Here is what they look like:

Left — rolled and dried leaves, ready to make tea. Right — an opened bud, after being used.

The opened bud on the right gives you a good idea what the leaves look like on the tea tree. Workers pluck these small buds from the trees and place them in baskets; the finest buds are plucked early in the spring.

Aside: Some Equipment

For best results it’s important to use pure water. Tap water produces a discolored tea with a foul taste. We get good results filtering our water in a Britta filter. In fact, we judge that it’s time to change the filter when our tea changes taste. The Britta instructions recommend changing the filter every two months, but we find it needs to be changed every month if our tea is to retain its flavor.

If you make tea often, it’s helpful to have a hot water dispenser, like this one from Zojirushi, along with your Britta filter:

Tea is best when the leaves have steeped for about 5 minutes. Since you may take much longer to drink the tea, it’s important to steep the tea in a separate container from your drinking mug. Here’s what we use:

Left — An Asian “busy person’s” tea-pot. A container at top holds the tea leaves and enough water to make a single cup. When the leaves are done steeping, pressing the red button drains the water into the pot, after which it can be poured into a mug. Right — an airtight container we use to store our tea leaves.

Alternatively, Asian supermarkets sell teacups in 3 parts — a mug, a container to hold the tea leaves, and a lid to cover while the tea is steeping. They look like this:

The tea leaves go in the removable upper part; when it is removed the tea drains through the holes in the bottom into the mug. After drinking a cup, the upper container with the leaves can be put back in and more hot water added to steep another cup.

Making the Tea

To make the tea, place 15-20 rolled buds into the leaf container, and add hot (near boiling) water. Taiwanese green tea typically requires 3 to 5 minutes to steep, and the tea is actually yellow, not green.

Shou-Ching likes her tea prepared the classic way. Add hot water to new leaves, and drain it after 30 seconds as the leaves just begin to open; this is thought to clean any impurities. Then add new hot water, let it steep 3 to 5 minutes, and drink this second batch. This produces a delicate, light yellow tea. Paul lets his steep a bit longer to make a slightly darker tea and adds a lemon slice. Here is what they look like:

Japanese Green Tea

Japanese green tea is made with a different process; the tea leaves are usually crumbled, not rolled. Here is what they look like:

These crumbled tea fragments are placed directly in the teacup and produce a green-colored tea. Yes, the tea leaves can be swallowed. Here is a comparison of a cup of Japanese green tea (left) with a Taiwanese green tea (right):

Obtaining Fine Teas

We are regularly sent tea by relatives and friends in Asia, so we haven’t had to shop for tea in the US.

However, Google searches turn up a number of vendors. “Tea from Taiwan” has some good-looking teas. Reader Gary Wilson kindly wrote to recommend Upton Tea Imports. And here are some Amazon links, not all currently available:

At roughly $1 per day, fine tea is not inexpensive. However, many people spend as much or more on coffee. Paul makes 5 or 6 cups per day from a single 4 g set of leaves, so the cost averages to only $0.20 per cup.

If your only knowledge of tea is derived from the Lipton Tea Company, we very much recommend that you give fine green or oolong teas a try! You might find tea more pleasant and enjoyable than you imagined.

Herb-Encrusted Salmon Cakes with Lemon Juice

Posted by on January 23, 2011 22 comments

We’ve been looking at cookbooks lately. We recently acquired The Garden of Eating by blogging stars Chef Rachel Albert (The Healthy Cooking Coach) and Don Matesz (Primal Wisdom).

The first thing one notices about this book is the impressive amount of effort that was put into it – 7 years, I’m told.  At 8.5” by 11”, 582 pages, it’s full of great recipes. Most pages present a single recipe plus variations.

The Garden of Eating synthesizes Paleo dieting with the foodways of traditional cultures. It begins with a discussion of Weston A Price’s survey of traditional cultures. From the Perfect Health Diet point of view, there are a few missing ingredients. There are recipes with potatoes or sweet potatoes, but no rice or taro. There are recipes with butter, but no cream. Still, potatoes and butter are a big step forward over some Paleo meal plans!

There are plenty of great dishes. We looked first for recipes with key Perfect Health Diet foods:

  • Salmon and beef are favored in our diet for their low omega-6 content;
  • Coconut milk and oil are favored for their ketogenic short-chain fats;
  • Lemons are favored for reasons I’ll discuss in an upcoming series on dietary ways to enhance immune function;
  • Herbs like oregano are favored for their antimicrobial activities in the gut.

We chose a recipe, “Herbed Salmon Cakes with Citrus,” that has a lot of these ingredients. Here is how we made it.

The Recipe

We doubled the size of the recipe, from 2 pounds salmon to 4 pounds, because we had a few college students at home for the holidays.

The recipe begins by pulverizing the fish in a food processor and combining it other ingredients in a bowl. We used a wok and here is the salmon with onion:

Other ingredients include fresh parsley leaves, minced celery, grated carrot, eggs, minced dulse leaf, herbs (basil, rosemary, thyme, oregano, lemon pepper), lemon zest, some starch, and some broth.

We made two substitutions: for the starch we used tapioca starch, while the recipe calls for shan yao, arrowroot starch, or powdered rolled oats; and we used lemon juice in place of the broth, where the recipe calls for chicken broth or filtered water.

Here are the ingredients mixed in our wok:

The next step was to divide into portions, form into balls, and press into patties. The patties are then covered and refrigerated overnight, or at least for several hours.

The recipe calls for lining a 13x9x2 baking pan with unbleached parchment or using muffin tins, and arranging the patties on a lightly oiled surface. We used aluminum foil on a cookie sheet and greased it with butter:

We cooked for 15 minutes at 350ºF until the patties were opaque throughout. Here’s how they came out:

It appears our mix was a little too watery and bled a bit. Maybe the tapioca starch isn’t right for this recipe; or maybe we didn’t use enough seaweed. One of the variations was to replace the dulse with sea salt; we had a shortage of dulse and forgot to put in the sea salt, so perhaps that was the cause.

No matter; it tasted great. Here it is on a serving plate:

The recipe suggests dipping the cakes in one of the cookbook’s many sauces: Cajun Ketchup, Better Barbecue Sauce, herb infused Mayonnaise, or Tahini Tartar Sauce.

We found the cakes to be addictive:  the more you ate the more you wanted another.

There’s a lot to be said for this recipe, apart from its healthy ingredients. The marinade takes away most of the fishy flavor, and the herbs cover the rest, so this may be palatable even to those who dislike salmon. Also, the cakes are a very portable form of salmon, easy to pack for lunch at work; they can be eaten as finger food.

Conclusion

We give two thumbs up to the recipe and the cookbook. Here’s a link to its Amazon page:

Dieter’s Dessert: Taro Coconut Cream Soup

Posted by on January 16, 2011 29 comments

Since we’ve started the topic of weight loss, it seems a good time to discuss the sort of dessert one should eat while on a calorie-restricted diet.

Almost any mix of a carbohydrate with a fat can serve as a dessert. Sweeter desserts use more sugar, less starch.

The following principles can guide the design of a Perfect Health Diet weight loss dessert:

  1. Ketogenic fats, such as those in coconut oil, are the best fat source. Ketones can evade certain kinds of metabolic damage, lower blood sugar levels, contribute to metabolic recovery.
  2. Dieters should maintain their regular carbohydrate and protein consumption, since the recommended Perfect Health Diet amounts are calibrated to meet nutritional needs and malnutrition must always be avoided.
  3. Dieters should avoid fructose, a toxin. Carbs are best obtained from starches or from fructose-free sugars like dextrose (the monosaccharide of glucose) or maltose (the disaccharide of glucose).

Here’s one dessert that meets those guidelines. It’s a common Asian-Pacific dessert: Taro Coconut Cream Soup.

First, gather your starches. Here we’re dicing some (already cooked) taro that was leftover from dinner:

Tapioca pearls make another nice addition to the soup. They are white before cooking, but will become transparent when fully cooked:

Put a can of coconut milk in a pot and warm it to the boiling point. You can add up to an equal amount of water if you prefer a less thick soup:

Add tapioca pearls and taro, and simmer for 10-15 minutes until the tapioca pearls are transparent. You may need to stir from time to time to make sure nothing sticks to the bottom:

Once it’s warm and the pearls are cooked, transfer some to a bowl. Here Paul has added a bit of coconut oil for some extra fat, some lemon juice, and cinnamon:

Lemon juice is beneficial to health, for reasons we’ll explain in an upcoming series on enhancing immune function. Lemon juice adds sweetness but has only 7 calories per fluid ounce. Cinnamon increases insulin sensitivity, which is probably desirable for weight loss. Both add to the flavor of the dessert.

There it is – a Perfect Health Diet dessert for those on a diet!

Shou-Ching is not on a diet, and decided to sweeten hers with some clover honey. She also included some leftover sweet potato chunks:

An Aside About Sweet Potatoes

Last week we had a discussion about different kinds of sweet potatoes and yams. So we bought a sampling.  Here, clockwise from upper right, are an American sweet potato (orange), a Korean sweet potato (large and yellow), and a Japanese sweet potato (small and yellow). The last two are botanically yams, not sweet potatoes; they are starchy and not nearly as sweet as the American sweet potato.

The Korean sweet potato is what we eat; it has a pleasant chestnut flavor. I thought the Japanese sweet potato was excellent also. American sweet potatoes are too sweet for my taste.

What’s the Trouble With Sweet Potatoes?

Posted by on January 11, 2011 166 comments

We’re continuing with a series on people who have reported something going wrong when they tested some variation of the Perfect Health Diet. (The first post summarized experiences, good and bad; the second looked at difficulties suddenly adding carbohydrates to a very low-carb diet.)

The next issue was reported by Chris Masterjohn; he had trouble with sweet potatoes:

Although sweet potatoes are considered a safe starch on the Perfect Health Diet, they are not very safe for me. When I discovered how yummy sweet potato fries are, I started eating several sweet potatoes per day. Within a few days, I was limping and my neck was stiff. By the end of the week, my limp was extreme. I looked online to see if I was eating anything high in oxalates, and sure enough, sweet potatoes are loaded with them. My symptoms dramatically improved after one day off sweet potatoes and were gone the second day.

Chris’s commenter Lisa also had trouble with sweet potatoes:

I’ve been very achy since I started eating sweet potatoes daily. Why would some of us be maladapted to oxalates?… I’m wondering if after a long stint of LC/paleo eating I’ve become intolerant to oxalates or to starch in general.

Clearly sweet potatoes are not safe for everyone. What might be causing the trouble?

Fructose and Fiber as Possible Confounders

One factor to consider is that there are different varieties of sweet potato. We eat an Asian sweet potato variety which is not nearly as sweet as conventional American sweet potatoes; it has a yellow flesh and a chestnut flavor. It is botanically a yam, not a sweet potato. It looks like this (via “my super sweet twenty-six”):

Like so many modern foods, the standard American sweet potato has been bred for sweetness. Here is data from http://nutritiondata.com comparing 100 g of potatoes, yams, sweet potatoes, and grapes for sugar, starch, and fiber content:

Food Sugar (g) Starch (g) Fiber (g)
Potato 1.2 17.3 2.2
Yam 0.5 23.1 3.9
Sweet potato 6.5 7.5 3.3
Grapes 15.5 0.0 0.9

All have similar calories. Yams are largely sugar-free, but sweet potatoes are intermediate between grapes and potatoes in both sugar and starch content. They are sort of half fruit, half starch.

Thus, it is conceivable that sweet potatoes could trigger an issue like fructose malabsorption; or that fructose or fiber might feed certain gut infections that would not be similarly fed by potatoes.

Oxalate

Chris believed his problem was due to oxalate. Sweet potatoes do contain oxalate, although they are not the only plant foods which do.

In fact, by far the largest source of oxalate in the American diet is spinach. Spinach by itself accounts for over 40% of all oxalate consumed by Americans; potatoes for about 10%. [1] Wheat bran has high levels of oxalate.

Why are oxalates troublesome?  Some people have sensitivities to oxalate. Rarely, genetic defects in the enzymes that degrade oxalate cause a disease called primary hyperoxaluria; this disease afflicts 1 to 3 people in a million.  Other conditions can elevate calcium or oxalate in the urine and increase the risk of calcium oxalate kidney stones. This is especially likely in people who are deficient in magnesium or who don’t eat citrate. [2]

Another pathway by which oxalate might cause trouble is via fungal infections. Candida and other fungi form calcium oxalate crystals in tissue [3,4]; fungi appear to be responsible for the yellow-brown calcium oxalate biofilms which form on stone monuments. [5]

But the literature suggests that oxalate sensitivities are rare. If oxalate sensitivity is present, then it should manifest itself when eating spinach, wheat bran, and other oxalate rich foods. Since Chris has praised spinach and wheat recently, I wonder if it is really the oxalate that caused his trouble.

Phytoalexins

Another possibility is a class of toxins called phytoalexins.

Ordinarily, sweet potatoes are largely toxin free. But when attacked by fungus or molds, sweet potatoes generate a variety of food toxins. As two papers describe them:

Sweet potatoes contain phytoalexins that can cause lung edema and are hepatotoxic to mice. At least one of these, 4-ipomeanol, can cause extensive lung clara cell necrosis and can increase the severity of pneumonia in mice. Some phytoalexins in sweet potatoes are hepatotoxic and nephrotoxic to mice. [6]

Ipomeanine (IPN), 4-ipomeanol (4-IPO), 1-ipomeanol (1-IPO), and 1,4-ipomeadiol (DIOL) are toxic 3-substituted furans found in mold-damaged sweet potatoes. IPN and 4-IPO are the most toxic, but all produce pulmonary toxicity in cattle and rodents, and 4-IPO induces hepatotoxicity in humans. [7]

Cattle will die if fed mold-damaged sweetpotatoes:

Unfortunate bovine fatalities occurring after ingestion of mold-damaged sweetpotatoes preclude the use of the culled tubers in livestock feed. In cattle, mold-damaged sweetpotatoes induce an acute respiratory distress syndrome resulting in asphyxiation. [8]

Toxins may be present even if mold damage is not visible:

Fermentation of 6 weeks duration was observed to inadequately eliminate the lung, liver, and kidney toxicity caused by mold-damaged sweetpotatoes. In fact, fermentation exacerbated the hepatotoxicity of mold-damaged sweetpotatoes. This is also the first demonstration that sweetpotato regions lacking visible mold damage can induce lung and kidney injury … [8]

Allergies

Sweet potatoes are generally considered to be one of the least allergenic of foods. However, infants sometimes do have sensitivities to sweet potato. This may reflect an immature gut flora in the infants; perhaps specific bacterial species — possibly including the oxalate-digesting Oxalobacter [9] — make sweet potatoes tolerable? If so, it raises the possibility that adults with incomplete gut flora might also have sweet potato sensitivities.

There is also the possibility of allergies to mold toxins in infected sweet potatoes.

Food Sensitivities as a Diagnostic Tool

Food sensitivities can sometimes be helpful in diagnosing certain health conditions:

  • Leaky gut. People with a leaky gut will have many food sensitivities; people with a healthy gut will have few.
  • Small bowel infections. People with infections of the small intestine will usually have a negative reaction to fructose.
  • Colonic infections. People with infections of the colon may react badly to fiber, and obtain relief on low-fiber diets.

There is a chance that oxalate may benefit fungal infections, so I suppose an oxalate sensitivity could be diagnostic for that, although in my experience fungal infections are usually slow-reacting to food and the response is rarely obvious.

Conclusion

In our book [p 121] we note that all plants make pesticidal toxins. Thus, no plant food can be guaranteed to be safe.

Normally, levels of pesticidal toxins are low in sweet potatoes. But it’s always desirable to inspect sweet potatoes for visible damage, and to discard any that are discolored or show other evidence of toxin production.

I confess to being puzzled as to how sweet potatoes caused Chris’s symptoms. If he tolerates spinach and wheat bran, it seems unlikely that the oxalate in sweet potatoes would be responsible. He might wish to test various foods and try to narrow down the source of his sensitivity.

For our part, we may cease listing sweet potatoes among our “safe starches” and specify yams instead, since a “safe starch” should probably be low in fructose.

References

[1] Taylor EN, Curhan GC. Oxalate intake and the risk for nephrolithiasis. J Am Soc Nephrol. 2007 Jul;18(7):2198-204. http://pmid.us/17538185.

[2] McConnell N et al. Risk factors for developing renal stones in inflammatory bowel disease. BJU Int. 2002 Jun;89(9):835-41. http://pmid.us/12010224.

[3] Takeuchi H et al. Detection by light microscopy of Candida in thin sections of bladder stone. Urology. 1989 Dec;34(6):385-7. http://pmid.us/2688263.

[4] Muntz FH. Oxalate-producing pulmonary aspergillosis in an alpaca. Vet Pathol. 1999 Nov;36(6):631-2. http://pmid.us/10568451.

[5] Pinna D. Fungal physiology and the formation of calcium oxalate films on stone monuments. Aerobiologia. 1993 9(2-3):157-167. http://www.springerlink.com/content/n72l71352t1r0r04/.

[6] Beier RC. Natural pesticides and bioactive components in foods. Rev Environ Contam Toxicol. 1990;113:47-137. http://pmid.us/2404325.

[7] Chen LJ et al. Metabolism of furans in vitro: ipomeanine and 4-ipomeanol. Chem Res Toxicol. 2006 Oct;19(10):1320-9. http://pmid.us/17040101.

[8] Thibodeau MS et al. Effect of fermentation on Sweetpotato (Ipomoea batatas) toxicity in mice. J Agric Food Chem. 2004 Jan 28;52(2):380-4. http://pmid.us/14733525. B76FN5FG89GM

[9] Hatch M et al. Enteric oxalate elimination is induced and oxalate is normalized in a mouse model of Primary Hyperoxaluria following intestinal colonization with Oxalobacter. Am J Physiol Gastrointest Liver Physiol. 2010 Dec 16. [Epub ahead of print]. http://pmid.us/21163900.