Nutty Wordy Wednesday

I mentioned in a previous post that my plant-loving friend Amanda helps me think about how the function of a plant part affects its nutrient content. I also put quotes around "nut" in referring to peanut butter, sunflower butter, etc. I know tahini is from sesame seeds and peanuts are legumes, but what makes a nut a botanical nut?

Nuts 2 by Steffen Zahn

The Nut: a one-seeded hard-shelled fruit. Includes chestnuts and hazelnuts; excludes almonds and walnuts (drupes).

The Legume: the fruit of a plant in the Fabaceae family. Includes peanuts, soy, peas, and carob.

The Seed: a small embryonic plant: embryo, nutrient supply, and coat. Angiosperms are enclosed in fruit; gymnosperms are not. Includes cereals, legumes, and nuts.

Seeds are the botanical basket that contain plant protein and oil sources. True nuts are fewer and farther between than I'd imagined. And nutrient profiles are all over the map. For example, chestnuts have an ω-6:ω-3 ratio of 9; hazelnuts, 90. Another - kidney beans sit at 0.6; and garbanzo beans at 26. All the more reason to eat a variety of plant foods!

"Nut" Butters and You

I met Amanda when we both worked in Dr. Chery Smith's Community Nutrition Lab; she as a Ph.D. student, I as a research assistant. To pursue research more up her alley, she switched to the Plant Biological Science program, but we're still friends. In fact, her focus on plants helps me think about how the function of the plant affects its nutritional content. For example, root tubers store nutrients to survive one year to the next, so they will contain a lot of starch for energy.

At a decidedly nutrient-poor and calorie-dense brunch at Bonnie's Cafe this Sunday, Amanda inspired me to consider the relative benefits "nut" butters, specifically sunflower seed butter and peanut butter and their respective omega-6 to omega-3 ratio. We want a low ω-6:ω-3 ratio because ω-6 fatty acids are inflammatory, but Americans tend to consume diets with a high ratio due to low vegetable and fish intake and high seed oil intake.

Not content with a simple comparison of two food items, I pulled together data from six different butters and five parameters, using the USDA's nutrient database as found here. Most desirable numbers are in green, least in red.

Selected nutrient contents of selected "nut" butters

per oz (~1.5 tbsp)	Almond	Cashew	Sunflower	Sesame	Peanut	Soy*
Protein:	4.2g	4.9g	5.5g	4.8g	7.0g	5.3g
Fiber:	1.0g	0.6g	N/A	2.6g	1.7g	2.3g
Calcium:	75.6mg	12.0mg	34.2mg	119mg	12.0mg	~45mg
Iron:	1.0mg	1.4mg	1.4mg	2.5mg	0.5mg	~0.3mg
ω-6/ω-3 ratio:	28:1	48:1	476:1	57:1	181:1	7:1

* Estimated from I. M. Healthy SoyNut Butter's nutrition label.

This chart does not make sunflower butter look very good: negligible fiber, middling calcium, and an atrocious ω-6:ω-3 ratio. Peanut butter takes the lead in protein content, ties cashew butter for last in calcium, and has the second highest ω-6:ω-3 ratio. Sesame seed butter (tahini) does quite well with top scores in fiber, calcium, and iron - too bad it tastes so bitter. 

And the winner in the fatty acid category is... soy. Surprised? What "nut" butter(s) do you eat, and why? And why do I keep putting "nut" in quotes?

Floral Wordy Wednesday

Gut flora predominates this week, as prompted by an article in Diabetes Forecast. This article explored the connection between intestinal bacteria and obesity, Type 2, and Type 1. Let's get to know two phyla in particular. (Need a refresher on biological classification? I did.)

The Firmicutes: a phylum of bacteria, mostly Gram-positive. You might recognize such genera as Bacilli, order Lactobacillales (think yogurt); and Clostridia (think botulism). 

The Bacteriodetes: another phylum, comprising the classes Bacteroidetes, Sphingobacteria, and Flavobacteria, which are not as much fun as they sound.
What's the significance of these two broad groups? Jeffrey Gordon of Washington University in St. Louis leads the pack in showing that obese and lean animals and humans have different Firmicute/Bacteroidete ratios. Specifically, obese mice have more firmicutes and fewer bacteroidetes. Similarly, obesity in humans is associated with altered gut flora and decreased bacterial diversity.

The difference, according to the DF article, is because firmicutes more efficiently ferment indigestible polysaccharides to produce short-chain fatty acids. That is to say, the firmicutes can digest starches we can't and make energy for us to use better than bacteroidetes can. Better energy extraction leads to more fat storage leads to gaining weight more easily.

As if that weren't enough, gut microbiota changes after gastric bypass surgery, the latter of which has profound effects on Type 2 diabetes. "Profound" as in "goes into remission." Gut flora strikes again.

There's still more: in a small study published in Nature, children who went on to develop Type 1 diabetes saw a decline in firmicutes and an increase in bacteroidetes, while their case-controlled match saw the opposite trend. Furthermore, the healthy children had more abundant bacteria overall. This study is too small to draw firm conclusions about the hygiene and/or leaky gut hypotheses, but it's fascinating nonetheless. And props to Giongo et al. for quoting Tolstoy.

Gluten Freedom

As I mentioned last Monday, I decided to spend a week avoiding gluten so I could get a taste of what those diagnosed with Celiac's disease experience. 

Steering clear of wheat was entirely manageable for me. I am not wedded to traditional breakfast foods, so potato slices with curried tuna salad suited me just fine many mornings. I lunched on Trotter's granola with yogurt or chicken rice salad, and dined on soups and stir-fry. Cheese topped daikon or apple slices rather than crackers, peanut butter was consumed straight from the spoon, and cabbage made crunchy chips for dip. Chocolate safely satisfied my sweet tooth.  

this is the way we slice our daikon, by supertrixiecat.

While I didn't suffer much from lack of bread or cookies, partly because I knew I could have them again soon, I was surprised by smaller challenges.I decided from the start that I would follow the spirit of the gluten-free diet rather than the letter. I would avoid obvious manifestations of the protein and make some exceptions for when I was at work. This freed me to eat granola (oats are often contaminated with gluten), taste soups with roux, or test pasta for doneness. 

But after Wednesday's post, I realized that the spirit of the gluten-free diet is total abstention from gluten. I should choose the gluten-free granola. I should brush the bread crumbs off the cutting board before using it. I should check to make sure I'm using wheat-free tamari before I sprinkle it all over the stir-fry. Then I began to understand the full challenge of being really gluten-free.

This experiment has brought all sorts of questions to my attention. For example, my aunt mentioned that a possible hazard of the gluten-free diet is a decrease one's tolerance to gluten. I've found other reasons to think twice about a gluten-free diet, but they will have to wait for another post.

Glutinous Wordy Wednesday

gluten /’glōōtn/ ►n. a substance present in cereal grains, esp. wheat, that is responsible for the elastic texture of dough [16^th C.: via Fr. from L., lit. ‘glue.’]

More technically, gluten is a protein composed of a prolamin (high in the amino acid proline) and a glutelin. In wheat, these are gliadin and glutenin. In barley, the prolamin is hordein; in rye, secalin.

(a) gluten = (b) elastic glutenin + (c) viscous gliadin.
(From H. Charley and C. Weaver. Foods: A Scientific Approach, 3rd ed., 187. 1998.)

These specific peptides (sequences of amino acids that make up a protein) cause all the trouble for those with Celiac’s disease. According to Krause’s Food and Nutrition Therapy, these peptides resist gastrointestinal enzymes and are not completely digested. Thus they are free to set off an autoimmune inflammatory response in a susceptible person, leading to all sorts of ‘mals’: malabsortption, malnutrition, malignancy, not to mention villous atrophy.

I suspect a phrase in that last paragraph jumped out at some of you: “not completely digested.” You’ve been vaguely suspicious of gluten for a while now. Does it really skulk around in our GI tract, dodging digestion?

Apparently, yes. According to the UCSD Wm. K. Warren Medical Research Center for Celiac Disease, “Gluten is resistant to proteolytic [protein-cutting] digestion… This is because there is a relative lack of enzymes with prolyl endopeptidase activity in human small intestine [remember how gluten’s proline-rich?].” In fact, scientists are investigating bacterial endopeptidases that destroy the triggering amino acid sequence in gliadin with hopes of developing an oral supplement, similar to lactase pills.

Does this mean you should extirpate gluten from your diet? I wouldn't say so. However, I have no great love for grains. Whole has a nutrient edge over refined, of course, but a baked potato trumps even brown rice, spaghetti squash beats whole wheat spaghetti, and so on. In caloric terms, a PB&J will have more calories than my childhood favorite, peanut butter on a spoon, even if you dot it with raisins.


Bottom line: Eat more vegetables, substituting them for grains when probable.

Definition from The Oxford College Dictionary, 2nd ed., 2007.