You Are What You Don't Eat (Part 2)

I'll just jump straight into today's topic: AGEs and methionine. If you feel like you have no clue about what I'm saying here, please go check the first part of this post, which was published last week. One thing's for sure, though! We're discussing serious matters, like longevity-promoting diets and nutritional problem-makers, aka those compounds that we cannot realistically eliminate from our diets, but which we should really try to keep an eye on. So, as A's go first...

Advanced glycation end-products (AGEs)

Glycation is a metabolic process in which a sugar molecule attaches itself to a protein or lipid molecule, impairing its function. In plain English, we'd probably call this hijacking. Glycation is usually followed by all sorts of reactions that culminate in the production of advanced glycation end-products or AGEs. Such an appropriate name, as AGEs have been associated with many age-related chronic diseases, like cardiovascular diseases, cancer or Alzheimer's. Interestingly enough, glycation can be formed both outside, as well as inside of our bodies. 

Exogenous glycation is produced by cooking proteins or fats at high temperatures and/or for a long time. Think about grilling meat, baking cakes or roasting chicken. On the other hand, endogenous glycation occurs after the absorption of simple sugars in the bloodstream. That is, after dessert. If by now you don't hate glycation as much as I do, do not forget about wrinkles. Skin proteins like collagen and elastin are also threatened by sugar molecules and their glycation potential.

In order to optimize your diet it would be preferable to monitor your AGE intake. Here is a table that lists the AGE content of 549 foods, based on carboxymethyllysine content and which might come in handy for grocery shopping and cooking.

Methionine

Methionine is an amino acid whose dietary restriction has been associated with several health benefits, including an overall life span extension. Here is an excerpt from a study conducted in 2003 on the effects of methionine restriction (MR) in rats.

MR has repeatedly resulted in life span extension comparable to that seen in energy restricted animals. In one of our typical studies using Fischer 344 rats, MR resulted in a 42% increase in mean survival and a 44% increase in maximal longevity (Fig. 1). While living longer, animals on MR grow significantly less (Fig. 2), and consume more food when food intake is expressed on a per body mass basis. This latter observation has led to some controversy, since when expressed on a per animal basis, MR rats, being smaller, consume slightly less food per animal than their C-fed counterparts. This has left open the possibility that the effect of methionine restriction on life span is secondary to a restriction of caloric intake, and not due to methionine deficiency. In order to examine the

proposition that MR might be an effect secondary to CR, we have pair-fed rats, so that animals consumed control diet in the same quantity as consumed by methionine restricted rats. Since animals fed in this way will consume exactly the same energy levels regardless of which diet they consume, this would exclude caloric intake as an explanation for the MR effect. When C rats were fed in quantities equivalent to that consumed by MR animals they consumed all of the food offered, and there was a modest reduction in weight gain relative to ad libitum fed C animals. However, there was no prolongation of life span (Fig. 3) associated with the slightly reduced food intake and body size (Fig. 4), indicating that life span extension associated with restricted methionine intake is not primarily due to reduced energy consumption.

(J. A. Zimmerman, V. Malloy, R. Krajcik, N. Orentreich, 'Nutritional Control of Aging', Experimental Gerontology, 2003, Jan-Feb: 47-52.)

Furthermore, the effects of a methionine deficient diet on glucose, T4, IGF-1 and insulin levels have been depicted in a 2005 study on mice.

A diet deficient in the amino acid methionine has previously been shown to extend lifespan in several stocks of inbred rats. We report here that a methionine -deficient (Meth-R) diet also increases maximal lifespan in (BALB/cJ x C57BL/6 J)F1 mice. Compared with controls, Meth-R mice have significantly lower levels of serum IGF-I, insulin, glucose and thyroid hormone. Meth-R mice also have higher levels of liver mRNA for MIF (macrophage migration inhibition factor), known to be higher in several other mouse models of extended longevity. Meth-R mice are significantly slower to develop lens turbidity and to show age-related changes in T-cell subsets. They are also dramatically more resistant to oxidative liver cell injury induced by injection of toxic doses of acetaminophen. The spectrum of terminal illnesses in the Meth-R group is similar to that seen in control mice. Studies of the cellular and molecular biology of methionine-deprived mice may, in parallel to studies of calorie-restricted mice, provide insights into the way in which nutritional factors modulate longevity and late-life illnesses. 

(R.A. Miller, G. Buehner, Y. Chang, J. M. Harper, R. Sigler, M. Smith-Wheelock, Methionine-deficient diet extends mouse lifespan, slows immune and lens aging, alters glucose, T4, IGF-I and insulin levels, and increases hepatocyte MIF levels and stress resistance, Aging Cell, 2005 Jun:119-25)

You can check the methionine content of a large number of food products at this link.

Finding your path through the valley of calories, glycemic indexes and loads, AGEs and methionine is not easy, but, in time and with the right amount of determination, it will eventually work out for you and for the goals that you have set for yourselves. The good part is that it's not rocket science. The bad part is that it might be even more demanding than that. But, in the end, what matters is that you stay true to yourselves and if living a long healthy life is what you care about, then reviewing these lists every now and then might be one of the tools to help you reach just that!

If It Tastes Good, Spit It Out!

Let's be honest here. Few of us have ever been mesmerized and lost our frenzied taste buds to the savor of raw kale! Do you agree?  More often than not, we love eating foods whose taste is characterized by intensity, be it in the salty or in the sugary direction, or which give us that feeling of abandonment into the warm and cozy fullness of our stomachs. Surprisingly, some of our most cherished food products are experts at pushing all our culinary buttons. Many drinks do not only contain large quantities of sugar, but also salt. Just add some salt to your sweetened cocoa, for instance, next time you have it and see what happens. Hmm...this post wasn't supposed to persuade you to drink sweetened hot cocoa, but you know what I mean.

Most of the foods that have made it on my diet black list are there for one common reason: glycation. Glycation is a metabolic process in which a sugar molecule attaches itself to a protein or lipid molecule, impairing its function. In plain English, we'd probably call this hijacking. Glycation is usually followed by all sorts of reactions that culminate in the production of advanced glycation endproducts or AGEs. Such an appropriate name, as AGEs have been associated with many age-related chronic diseases, like cardiovascular diseases, cancer or Alzheimer's. Interestingly enough, glycation can be formed both outside, as well as inside of our bodies. 

Exogenous glycation is produced by cooking proteins or fats at high temperatures and/or for a long time. Think about grilling meat, baking cakes or roasting chicken. On the other hand, endogenous glycation occurs after the absorption of simple sugars in the bloodstream. That is, after dessert. If by now you don't hate glycation as much as I do, do not forget about wrinkles. Skin proteins like collagen and elastin are also threatened by sugar molecules and their glycation potential.

So, without further ado, let me present to you my food renegades:

• Added fructose 
• Glucose
• Starches
• Fried products
• Grilled meat
• Additives and preservatives

It's so hard to avoid those AGEs when it's summer, with its barbecue and ice-cream temptations. Ah well, I guess it must be equally difficult in the winter too, when in Budapest, for instance, mulled wine and kurtos kalacs (chimney cake, in a rough translation) are everywhere. The point is, nonetheless, that there are always occasions and there are always excuses for a cheat. But the good news is that cheats are OK every once in a while and as long as they remain that: cheats.

On the Foods that I'd Take Along on a Foodless Island

Because some of you have asked me about this before, here it is: the (disappointingly restrictive) list of foods that I believe to be the best for promoting healthy longevity. During the many hours that I've spent researching and thinking about this topic, I've come to learn that all of the things we eat have both pluses and minuses. Fish and seafood, for instance, are excellent sources of omega-3 but they also contain mercury. Green tea is known and revered for its antioxidants but  (1) it blocks iron absorption, while (2) the newest research in this area has started questioning our way of understanding the relationship between antioxidants, free radicals and molecular damage. Personally, the way I go about designing the optimal longevity-promoting lifestyle is to try to incorporate in my diet mostly those foods that overall benefit my body more than they harm it.

So here are my top choices:

• Water (don't laugh; water is underrated)
• Vegetables and tomatoes
• Fish and seafood (approximately 200 grams divided into smaller portions throughout the day)
• Seaweed
• Avocados
• Lemons and limes
• Ginger and fresh ginger tea
• Turmeric
• Green and white tea (at most 2 cups a day and not during or shortly after meals)
• Cranberries (for women)

Foods that almost made it on the list:

• Blueberries
• Pomegranates
• Apples

A healthy diet is all about optimizing both macros and micros. Obviously, it is impossible to consume only the items on this list, but I do think that it is preferable to build your meals around them, while adding here and there other foods that do not harm you more than they benefit you, like beans, lentils, chicken, nuts, just to give a few examples. 

If you enjoyed this post, stay tuned! Next week I'll be writing about those foods that I believe is best to try to avoid at all costs. In the meantime, please feel free to share your favorite longevity tips.