Garlic

People often say that garlic has medicinal properties. Some claim it lowers blood pressure, others swear it helps cholesterol and reduces clotting, and some even think it protects against cancer. I’ve also heard that garlic is “healthier” 10-15 minutes after it has been crushed or minced. Is any of this true?

The Science of Single Foods

As someone who regularly reads the scientific literature on the health benefits of food I can assure you that this is not an easy question to answer. The problem is that the effect of any single food on human health is likely to be small at best, and small effects are very difficult to detect with reliability. Studies must be incredibly well-designed to contribute anything of value to our understanding of how a food works in the human body. Also, many studies must be taken together in context for the data to be evaluated properly.

I have been researching this garlic question on and off for months and feel only slightly more confident today than I did when I started. To summarize, there are a good number of studies addressing the health value of garlic, but very very few of them are well-designed and published in reputable journals. The problem with having a large number of poor-quality studies is that results are often conflicting and difficult to interpret. Thus, when another scientist comes in to do a meta-analysis (pooling data from many studies and re-analyzing it for stronger statistics) the findings are usually inconclusive.

However, inconclusive findings do not enable me (or anyone) to say there is no benefit. What I can say is that more research is needed and if there is a benefit it is likely to be small. (How unsatisfying is that?!). But personally I would still recommend eating garlic for health. Why?

Small Benefits Are Important

Although we cannot say exactly why garlic is good for you, it is almost certainly not bad for you. Moreover, although it is difficult to attribute a particular health benefit to a single food, we do know that people who eat the most vegetables tend to be healthier than people who fewer.

Many nutrition scientists are beginning to suspect that the benefit of foods like garlic are primarily relevant in the context of a whole diet and cannot be evaluated independently. This means that it is less important that the individual studies I mentioned earlier are inconclusive, because they are likely not sensitive enough to evaluate the complex interactions of whole foods and food combinations on human physiology.

The Best Reason To Eat Garlic

The most important thing you can do for your health is eat a diverse diet of natural, unprocessed foods. Garlic is an amazing ingredient that imparts a unique and wonderful taste to the food it is cooked with. If you like garlic and it encourages you to eat your vegetables, then it’s good for you.

If it makes you feel slightly better knowing that it may help your heart or reduce inflammation, that’s awesome but less important.

What About The Crush?

If you do hope garlic can add to your health, is there any benefit in crushing it early? Probably.

Scientists have long suspected that the active ingredient in garlic is a substance called allicin. A recent study from Queen’s University showed that it is actually a decomposition product of allicin that has the most potent antioxidant activity.

Interestingly, allicin is created from an enzyme called alliinase that is not released from plant cells until they are damaged. Alliinase is what gives garlic (and onions) their strong odor and is thought to be a self-defense mechanism for these plants. When garlic is crushed, alliinase becomes active and begins creating allicin. As allicin is created and breaks down, the antioxidant potential of garlic is dramatically increased. Optimal antioxidant levels are created about 10 minutes after garlic is crushed.

It has not yet been shown that this increased antioxidant activity is a benefit to humans, but the principle is compelling enough to try to remember to crush your garlic a little early. If you are anything like me though, this feat is almost impossible. Apparently garlic hasn’t done that much for my memory.

What are your favorite reasons to eat garlic?

Originally published March 27, 2009.

Tags: allicin, alliinase, crushed garlic, garlic, minced garlic

Photo by Mr. T in DC

“I’ve always wondered what the scientific perspective of alcohol consumption is. I have been doing some research but the actual effects of it on the body range from beneficial to cancerous.”

The clinical science on alcohol consumption is vast and diverse. It’s easy to find studies that demonstrate the benefits of alcohol, but it is equally common to find research showing its dangers. Sorting through the data is not trivial, and getting the right answer from news reports is virtually impossible.

Let’s start with the facts:

1. Alcohol is addictive

Alcohol addiction is one of the most well-understood and dangerous risks of drinking. A propensity for addiction can run in families, but can affect anyone who drinks in excess. None of the health benefits of alcohol can negate the destruction caused by addiction, and anyone who drinks should be careful to avoid this terrible condition.

2. Alcohol damages the liver

Alcohol metabolism occurs in the liver and can cause severe damage when consumed in large quantities. Liver damage can usually be reversed if alcohol consumption stops.

3. Alcohol is associated with breast cancer (sort of)

Drinking is weakly associated with an increased risk of breast cancer. This is likely because alcohol increases aromatase activity in the human body, which increases estrogen production. Estrogen imbalance is a known cause of breast cancer. However, the association between drinking and breast cancer is negated by sufficient folate intake. Folate or folic acid is a B vitamin found in leafy green vegetables, fruits and legumes (and fortified foods). In other words, a healthy diet protects against alcohol induced breast cancer risk.

4. Alcohol protects against mortality from heart disease

Drinking alcohol reduces your risk of dying from a heart attack by preventing blood clotting. This effect is not limited to red wine, all spirits elicit substantial protection. The association appears to be dose-dependent, meaning that the more you drink the more protection you get. HOWEVER, you start raising your risk for the above mentioned problems with every additional drink per day. For men the ideal dosage is 2 drinks per day, for women it is 1 drink per day.

5. Alcohol raises good HDL cholesterol

Moderate drinking also reduces your risk of getting heart disease in the first place by raising beneficial HDL cholesterol without raising LDL cholesterol. Low HDL is a serious problem in America, and alcohol could be a significant benefit for some people. Here are other ways to raise your HDL cholesterol.

6. Red wine may slow aging

Aging research has been revolutionized by the discovery of a compound in red wine called resveratrol. Resveratrol has been shown to slow aging substantially in several model organisms. Though the effect in humans is still unknown, red wine is associated with many benefits that seem to go above and beyond the benefits of alcohol in general.

7. Red wine may protect against Alzheimer’s disease

Several studies have shown that red wine is associated with a decreased risk for Alzheimer’s Dementia, a devastating neurodegenerative disease that affects 1 in 4 people over the age of 90. The mechanism of action is unclear, but the benefits may be linked to the effect of red wine on fatty acids in the blood (raising the good stuff), or by slowing the aging process itself.

8. Alcohol causes accidents and behavioral problems

Even relatively safe levels of drinking can be deadly when combined with poor decision making. If you do choose to drink alcohol, always be sure that you’re in a safe environment and can get help if you need it. Being safe sometimes, or even usually, is simply not good enough.

There are plenty of good reasons to avoid alcohol if you choose, and many of the benefits can be garnered by simply increasing the amount or intensity of your daily physical activity.

However, the evidence is pretty clear that moderate alcohol consumption (1-2 drinks per day) can improve health and may be an important component of a healthy lifestyle. This is even true for those who pick up the habit later in life.

And last but certainly not least, some of the best times of my life have been over a drink with friends. And I guarantee you most of us aren’t thinking about our heart health while enjoying a great bottle of wine. As long as you consider safety first, never forget that smiling is one of the healthiest things you will ever do.

Here’s a fun question: what’s your favorite drink??

Tags: alcohol, breast cancer, cholesterol, HDL, heart disease, wine

Enough people have asked me if the kind of cholesterol in egg yolks is good or bad (hint: it’s neither) that I think it is time for a brief tutorial on this misunderstood molecule.

Rather than put you to sleep with a watered down version of a Wikipedia article I decided to explain the interaction of diet and cholesterol in a short video. Hopefully this will help clear up what cholesterol is and how you should eat to minimize your risk of heart disease.

As always, feel free to drop me questions in the comments.

If you like this story follow me on the new Digg!

Further reading:

• How To Raise Your HDL Cholesterol
• Intact Grains vs Whole Grains
• How To Make Eggs Taste As Good As Bacon
• Book Review: Good Calories, Bad Calories

Tags: cholesterol, eggs, HDL, heart disease, LDL

Photo by Robyn's Nest

Artificial sweeteners and sugar substitutes can be very appealing to people looking to cut their calories or control blood sugar, and I get a lot of questions about them. Generally I don’t recommend processed or sweetened foods and encourage people to break free from regular sugar consumption, but I recently discovered coconut palm sugar and decided to look into it.

Coconut palm sugar has garnered attention as being a low-carb sugar substitute that is both more nutritious and sustainable than typical granulated sugar. Because of its complex flavor it is also gaining a reputation in foodie communities, with establishments like the popular Samovar Tea Lounge in San Francisco switching 100% of its sweeteners over to coconut palm sugar.

Pure coconut palm sugar is a natural product made from the nectar of the coconut palm tree. There are several different varieties of palm (Palmyra, date, etc.), and “coconut palm” specifically refers to the coco nucifera plant.

Most of the “palm sugar” commonly sold in Asian markets is not pure coconut palm sugar but is blended with other fillers such as white cane sugar. Pure certified organic coconut palm sugar is sold under the brand name Sweet Tree in the US, and can be found at some natural food stores. It is also available online.

The information in this article applies only to 100% pure coconut palm sugar. Check your labels carefully.

Pure coconut palm sugar reportedly has a naturally low glycemic index (GI)–a measure of how food impacts blood sugar–which has led some people to claim that it is a valuable sugar substitute for people with diabetes or those looking to control blood sugar (the low-carb camp). Indeed, a lower GI may be a good indication that a food is safer for diabetics, though it is not a guarantee.

When I first saw that coconut palm sugar has a low GI I figured it would be composed largely of fructose, similar to the popular sweetener agave nectar (and high-fructose corn syrup). Fructose does not impact blood sugar because it is transported directly to the liver and converted to fat. For an explanation of this mechanism, check out Dr. Lustig’s video on the dangers of fructose.

I was surprised to find, however, that coconut palm sugar is reportedly very low in fructose, and its main sugar component is sucrose (aka table sugar). What confuses me is that the GI of coconut palm sugar is supposed to be 35, while the GI of sucrose is 64.

I feel obligated to qualify the numbers on coconut palm sugar, however, since I could only find a summary of how GI was measured and not the published study itself. Also, this information was only available on the website of a company that sells coconut palm sugar. This doesn’t mean the number is inaccurate, it just means I’d like to see the study repeated by another credible source or two before taking it as fact.

The number of calories in coconut palm sugar is almost identical to the number in regular table sugar and its closer relative, brown sugar. But coconut palm sugar is notably higher in various micronutrients, probably because it is less processed than industrial sugars.

But does anyone really eat sugar for health benefits?

There are a number of good reasons to consider using coconut palm sugar as a substitute for white or brown sugar in your kitchen. For me the most obvious benefit is that it tastes amazing, similar to brown sugar but with a rich complexity I’ve never tasted in industrial sugars.

Coconut palm sugar is also supposed to be substantially better for the environment, having been called the most sustainable sweetener by the Food and Agriculture Organization (FAO) of the United Nations (couldn’t find the original FAO report though).

Overall coconut palm sugar is a tastier and possibly healthier and more sustainable substitute for granulated or brown sugar. I wouldn’t go so far as to call it a health food, or even low-carb just yet. However it is a nice pantry addition for foodies concerned with sustainable products.

Substitute coconut palm sugar for traditional sugar at a 1:1 ratio in normal cooking and baking.

Have you tried coconut palm sugar? What do you think?

Tags: coconut palm sugar, diabetes, fructose, glycemic index, sucrose, sugar, sustainable, sweeteners

Photo by Lord Jim

“What do you think of the Paleo diet which advocates zero grain consumption?”

The Paleolithic diet is one of the most rapidly growing diet trends of the past several years. Followers of the Paleo diet argue that humans have not evolved to eat agriculture-based foods and can only achieve optimal health by consuming a hunter-gatherer style diet. Thus the Paleo diet is completely devoid of grains and legumes, and also shuns dairy, salt, refined sugar and processed oils. The diet is composed primarily of meats, fish, vegetables, fruits, roots, nuts and seeds.

(The Wikipedia article on the Paleo diet is actually pretty good if you’d like to read up on the details. I particularly like the Opposing views section.)

Like most diets the Paleo diet has a little bit of good science behind it, but also a lot of logical leaps and baseless assumptions. The evolutionary argument that humans are somehow maladapted to agriculture-based diets is particularly unconvincing (resting on many unproven assumptions), yet is the fundamental premise on which the Paleo diet bases its recommendations.

The reasoning behind the Paleo diet is less interesting to me, however, than the impact of the diet itself. Will “eating like a caveman” really help you be healthier?

Possibly, but not necessarily.

The most obvious advantage of the Paleo diet is the lack of processed foods. There is ample evidence that societies on traditional diets boast far better health than those on modern, Western diets–and the hallmark of modern diets is food processing. Paleo diets therefore are low in sugar, refined carbohydrates, trans fats, excess salt and pretty much everything else that leads to “diseases of civilization.”

Paleo diets are also abundant in healthy, nutrient-rich foods such as vegetables, fruits, nuts, fish and meats. I have no doubt that anyone willing to stick to a Paleo eating plan will have a healthy weight and remain virtually free of heart disease, diabetes, hypertension and may even have lower rates of cancer.

But the question still remains, is it necessary to eat Paleo to be healthy?

This is where I take issue with the Paleo philosophy. While the promise of a diet free of processed foods is substantial, the Paleo diet goes beyond this and demands considerable sacrifice.

Paleo diets do not allow for any grains or legumes. This pretty much eliminates every traditional cuisine on earth including Japanese, Italian, Indian and Greek. Not only is this a culinary tragedy, it ignores the fact that these cuisines feed some of the world’s healthiest and longest-lived individuals.

Traditional, global diets that include grains and legumes but exclude highly processed foods have been some of the most successful for health. Diseases of civilization are only problematic in Western cultures where highly processed foods make up a large proportion of the calories consumed.

Proponents of the Paleo diet argue that it is necessary to eliminate grains and legumes because they contain “antinutrients,” substances that can interfere with the body’s absorption of other important vitamins, minerals and proteins. However, well-nourished individuals who eat a varied diet of unprocessed foods (including grains and legumes) are not nutrient deficient and are generally healthy.

Given that it is possible to thrive on a diet that includes some grains, legumes and even small amounts of processed foods, one must question if giving up the culinary joys of travel and global cuisine are really worth the sacrifice. In my experience, food substitutions and modified recipes designed to mimic traditional meals can sometimes be tasty but can never replace true authenticity.

Another contention I have with the Paleo diet is the assumption that the same eating patterns will work for everyone. People’s lives differ in countless ways. We each have different levels of daily activity, demands on our time and food preferences. We also have slightly different genetic backgrounds, which can result in significant differences in metabolism and hormone levels. These individual variations can make dietary needs different for each of us.

Scientific reports on health and diet almost always rely on data pooled over many people (sometimes hundreds of thousands), since this is the only way to measure statistical significance. As a result these studies only inform us about dietary health trends on a population level and tell us little about what will work for us individually. Differences among people may be part of the reason large nutrition studies so often fail to show meaningful results.

Thus, there may be a percentage of the population that has great success on the Paleo diet and finds it easy to stick to and achieve results. This is wonderful. However there may also be a segment of the population (myself included) that finds living without grains and legumes to be chronically unsatisfying and unsustainable.

Try telling a foodie they can never use salt, eat cheese or drink wine again and see how far you get pitching a Paleo diet.

If you currently eat a typical Western diet with little variety and many processed foods, tend to have better success following rigid diet plans, and have no qualms about giving up or modifying traditional meals to meet your dietary demands, then you might have luck following the Paleo diet. However there is no reason to believe it is the only path to good health.

The best diet is the one that works for you. Finding a healthstyle you can embrace and enjoy is essential if you want to build a lifetime of healthy habits.

Do you follow a Paleo diet? What do you think?

Tags: antinutrients, beans, diseases of civilization, intact grains, legumes, paleo diet, processed foods, trans fat