Showing posts with label protein. Show all posts
Showing posts with label protein. Show all posts

23 April 2015

Renewal. Retool. Remake.

This lyric essay is an adaptation of the piece I performed at April's MNFYP event, part of the storytelling series. The topic: renewal.

I read a poem last November, when the world was wrapped in mono gray. It was the climax of MyTake: A Story to Nurture in Five Food Groups.

As nature squeaks into color, life, and growth, this protean poem unfurls tightly packed stanzas into the broad notes of spring.

~~~~~~~~~~~~~~~~~~~~~~~
One thing broke me;
         two built me back.

Fall in FScN 4612, Human Nutrition,
each lecture softening the edges of my circumscribed truth.
Studies strive for stolid statements,
         but humans refuse to cooperate.
We fictionalize what we ate yesterday,
we guess at how often we eat fish,
we tick the same box for grass-fed beef,
         for venison,
         for McDonald’s Hamburgers.

I crumbled under the weight of peer-reviewed articles,
at odds with each other,
squinting their way to the truth.

Winter, and I watched a dietitian speak with precise passion
         of an ecological approach to food and health,
         of environmental health and natural resources,
         of starting with oneself.

Essential building blocks condensed
         into a strand stretching
         from a protein machine, bending and twisting
         into a tertiary structure,
The Food System.

Summer, and I was swept along on a sustainability safari:
landing in locations
         from labels off co-op shelves,
scuffling with scripts
         from scholars and scientists,
facing furrowed facts
         from farmers and foragers.

I transcribed novelty into neurons,
I put my hands into the blackness and pulled.
~~~~~~~~~~~~~~~~~~~~~~~

What is protein?

Amino acids line up according to ancient instructions, attract and repel each other, furl into microscopic protein machines, group and grow to make this protein machine, complex and communal.

21 March 2011

"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)AlmondCashewSunflowerSesamePeanutSoy*
Protein:4.2g4.9g5.5g4.8g7.0g5.3g
Fiber:1.0g0.6gN/A2.6g1.7g2.3g
Calcium:75.6mg12.0mg34.2mg119mg12.0mg~45mg
Iron:1.0mg1.4mg1.4mg2.5mg0.5mg~0.3mg
ω-6/ω-3 ratio:28:148:1476:157:1181:17:1
* 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?

26 May 2010

Calcium and protein: friends or foes?

In the last post, we saw that dairy products are a fine source of calcium, thanks to the absorption-enhancing property of lactose and the density of calcium by weight or calorie. So why consider anything else? I think many people have an idea that protein, in which dairy products are rich, interferes with calcium or bone health in some way. In the chapter on bone health in Krause’s Food and Nutrition Therapy, John JB Anderson states that “the relationship between protein and calcium is unsettled” (625).

Let’s take a step back. What is this relationship? On the one hand, protein is considered to have an anabolic (building) effect on bone. After all, around 25% of the bone matrix is protein in the form of collagen fibers. Calcium and phosphorus make up the hydroxyapatite that gives bone its rigidity. On the other hand, a chronically low intake of protein decreases the serum concentration of albumin, a protein that transports nearly everything in the blood, including calcium (Anderson, 625).

So why would high protein intake pose a problem? Here’s where the textbook gets a little fuzzy. First it says that “actions of proteins and their absorbed amino acids… [have] a catabolic [breaking down] effect resulting from the generation of an acid load” (625). But as far as I can tell, extracellular excesses of acid are buffered primarily by bicarbonate - calcium doesn’t have much to do with it.

The second reason given is that urinary losses of calcium increase following meals that contain large amounts of animal protein (625). The exact mechanism is not clear, but it may be because the sulfates generated by the metabolism of sulfur-containing amino acids (cysteine, cystine, methionine) bind to calcium ions in the kidney and prevent them from being reabsorbed (Gallagher, 115). A list of food sources of sulfur follows: meat, poultry, fish, eggs, dried beans, broccoli, and cauliflower. This is a bit misleading, as 3 oz of beef has fourteen times as much methionine as 1 cup of cooked broccoli.

Studies tracking protein consumption and bone fractures or bone mineral density are… numerous. Some come out in favor, some come out a wash. I would say that most people should consider getting more calcium from vegetables, and in the next post, I’ll explain why it’s a great idea.

Photo source: fooducate.com