Tag Archives: oxalic acid

Hiking at Sylvan Glen

IMG_0911Spring is in the air! I had a fantastic time hiking at the Sylvan Glen preserve yesterday. This interesting little preserve is in Westchester county near the Putnam county border. It’s close to Yorktown. I hiked about 4 miles with the hiking group I was with, which didn’t include any joggling since I did that earlier in the day and I didn’t want to distract anyone.

IMG_0941You can get fantastic views in some spots within the park, but be careful. The trails in this park can get very steep in some spots, so you need to be in good shape to make your way through.

IMG_0942The area near the gorge was once an important quarry. It has been abandoned for several decades, but there are still big piles of rock all over the place.

IMG_0961Sylvan Glen also has one of the oldest trees for miles around. This tree is several centuries old. It is probably a white oak, judging by the leaf litter around the tree. It’s been said by some arborists that oaks specialize in not specializing – hence, they grow almost everywhere. I hope this tree survives for another thousand years.

IMG_0974You know its spring when skunk cabbage(Symplocarpus foetidus) starts peaking through the ground. In the north-eastern U.S, it is very often the first green you will see in early spring/late winter. And yes, the plant does live up to its name.

It is an amazing plant due to its ability to produce a lot of heat. According to Craig Holdrege at the Nature Institute:

A couple of times I’ve been lucky enough to see spathes growing up through a thin layer of ice, the ice melted around the spathe in a circular form. This is an indication of skunk cabbage’s remarkable capacity to produce heat when flowering. If you catch the right time, you can put your finger into the cavity formed by the spathe and when you touch the flower head, your finger tip warms up noticeably. Biologist Roger Knutson found that skunk cabbage flowers produce warmth over a period of 12-14 days, remaining on average 20° C (36° F) above the outside air temperature, whether during the day or night. During this time they regulate their warmth, as a warm-blooded animal might!

Skunk cabbage is at best marginally edible if you boil it in 10 changes of water and leave it to dry for a few days. In other words, don’t bother. Native Americans would only eat it when nothing else was available.

If you try to eat it raw or with only a little cooking, the oxalic acid(partially responsible for the plant’s smell) crystals in the leaves will make you feel like you are having holes burned in your tongue.

What is oxalic acid? Oxalic acid is a powerful anti-nutrient that can block the absorption of calcium, iron and other important minerals. Although spinach(and some other vegetables) doesn’t have as much oxalic acid as skunk cabbage, it still has a significant amount. This is one of the reasons I don’t eat much spinach(I prefer kale and cabbage), and strongly advice others to avoid juicing spinach. Cooking spinach can reduce its oxalic acid content, but it won’t eliminate it.

IMG_0955The hike ended just after sunset. I had a great time with some very fun people, although we didn’t get to see much wildlife.

Radioactive Brazil nuts and the naturalistic fallacy


Brazil nuts. Source: Wikipedia

Believe it or not, just about all the food we consume has tiny amounts of radioactivity. Some foods contain more than others. While a small amount of it is due to nuclear fallout and industrial pollution, most of it is naturally occurring, since radioactivity is a natural phenomenon.

Brazil nuts by far are the most radioactive of all food. According to Wikipedia:

Brazil nuts contain small amounts of radium. Although the amount of radium, a radioactive element, is very small, about 1–7 pCi/g (40–260 Bq/kg), and most of it is not retained by the body, this is 1,000 times higher than in other foods. According to Oak Ridge Associated Universities, this is not because of elevated levels of radium in the soil, but due to “the very extensive root system of the tree”.

Even though Brazil nuts are a lot more radioactive compared to most foods(due to its deep, extensive roots), this doesn’t mean we should avoid them. The amount is way too small to have any permanent effects. This radioactivity in Brazil nuts is naturally occurring, not due to nuclear fallout.

Brazil nuts are an excellent source of selenium, an important mineral that some preliminary studies suggest may help prevent cancer, among other things. Fortunately, selenium deficiency is rare in most developed countries.

I think this also goes to show that eating “natural” doesn’t mean you are somehow avoiding very toxic substances. Radiation is perfectly natural, and so are lead and mercury, which are also present in trace amounts in the food and water supply. Luckily, these toxins tend to get quickly removed by the body.

While eating healthy usually means eating more “natural”(less processed foods, more whole/unprocessed foods), many health-nuts take this to extremes and buy into some form of the “naturalistic fallacy” to justify their dietary habits. This is especially true of people who follow a rawfood vegan diet, and also the followers of “paleo” diets.

At its most basic, the naturalistic fallacy means equating “natural” with being inherently good, safe, or desirable, while something “unnatural” is seen as inherently bad, or undesirable. Ask a rawfoodist to explain why they believe their diet is so much better compared to the way most people eat, and their answer ultimately boils down to: “It is more natural”. Cooked food is “unnatural”(what other animals cook their food?), so cooked food is bad; food in its raw, “natural” state is good.

This doesn’t mean there is no truth to the arguments in favor of eating raw. For instance, it is true that many nutrients are destroyed while cooking at high temperatures. On the other hand, many other nutrients are less bio-available in raw foods. It must also be noted that cooking helps destroy many anti-nutrients like oxalates or phytates that can interfere with the absorption of important minerals like iron(this is why raw spinach with its high oxalate content is a poor source of calcium and iron). This explains why you can’t eat beans raw(of course you can try to do it, but I wouldn’t advise it). While some foods like salad greens, nuts, and fruit are best eaten raw, many other foods, like legumes and grains have to be cooked.

While we should minimize our consumption of processed foods, and of both natural and synthetic toxins, we shouldn’t go overboard and panic if we discover something contains trace amounts of a toxic substance. Similarly, we shouldn’t demonize something just because it may contain something that is “unnatural”. Dogmatic black and white thinking is not helpful when it comes to healthy eating.


Radioactivity in nature