Category: Question

Posted on
by

From what I understand (non-expert), meat does not have any fiber. I know that some parts of plants are not digestible by humans such as soluble and insoluble fiber. Even though we can not use these molecules directly, they are eaten by gut bacteria and thus are important for a healthy gut microbiome. Having a vibrant gut microbiome has a variety of positive health effects from regular poops to less inflammation.

I am curious if the gut bacteria obtain nutrients from other molecules in food especially from meat. I know that meat doesn’t have fiber, but does it have other types of molecules that can not be digested by humans but that can be broken down and used by gut bacteria?

Part of the reason why I think this may be possible is that human breast milk contains oligosaccharides, which are not digestible but that are important for the gut health of new born babies. Does meat contain any molecules such as these that are not digestible by humans? What are these molecules?

I think there must be some molecules in meat that are not digestible because animals on a purely carnivore diets still have gut bacteria (see this paper for example). These bacteria have to eat something.

I also posted a version of this question on Biology Stack Exchange.

Posted on
by

I have been thinking of pasta, and the wheat it is made from, as a commodity. In my mind, it is all pretty much the same, a convenient and tasty source of energy. Recently, I came across organic pasta, and I am curious to know if there is a real difference between the organic and regular. If there is a difference, what are the benefits of organic?

I do not have first hand knowledge about how food gets to the grocery store. From what I’ve read, organic food certified by the USDA follows strict standards including restrictions on herbicides and pesticides and requiring plants be non-GMO (Genetically Modified Organisms). See for example this post by the USDA. I learned recently that some organic farmers even use fire to kill weeds. In contrast, regular farming of commodity crops like wheat involves heavy use of herbicides like RoundUp and GMO crops.

Here are some ideas about ways the organic food could be better:

  1. Less pesticide/herbicide residue.
  2. Happier, healthier plants leading to better tasting food.
  3. Maybe the non-GMO plants are better in some way.

The first reason seems plausible to me. If some substance is so deadly for weeds or for bugs can it be that great for me? But on the other hand, humans may not be affected because our biology is different than bugs or weeds or we may not be affected if the dose is too small.

The second reason, happier, healthier plants, also seems reasonable even though it is more subjective. I think of the difference in taste between food grown in home gardens and food we buy in the store. It seems reasonable that plants will thrive in an environment designed for them, instead of in a chemical warfare battleground.

The third reason, GMO, I’m not worried about except with how it plays into the first two reasons. Selective breeding has been used for ages, and breeding modifies plant genes. From what I have read, genetic modification really seems to be fine. The only concern I have is that farmers might drench the hardy GMO crops in herbicide and pesticide to make it easier to handle weeds and bugs. It seems like that could lead to more pesticide residue and it might be rough on the plants as well.

Are these ideas about benefits of organic food accurate? Are there other benefits to organic food? What are reliable sources for answering these questions?

How does the organic food affect our health? It seems that more people have trouble digesting wheat than they used to. Could farming practices be partially to blame, and could organic wheat help?

Posted on
by

I have been wondering about the long term prospects for the economy as I am trying to get things like retirement accounts and a 529 savings account set up. All the investment advice talks about the wisdom of holding stock for the long term. This advice makes sense because for the past few hundred years, there has been continual exponential economic growth (see great exploration of the economic growth at Max Rosen’s Our World In Data site).

But I am skeptical of anything growing exponentially forever. Exponential growth is relentless; it keeps getting faster and faster. There are lots of things that grow exponentially for short amounts of time, most commonly populations whether they are bacteria, rabbits, or people. At some point something will limit the growth. Are economies different? Can they grow exponentially forever?

I have read articles arguing both ways. The optimists feel that we will keep on innovating our way to growth (see for example a Freakonomics post). The pessimists (or realists) argue that economic growth is tied in some way to energy use (for example see this blog post). Consequently if we kept economic growth going then at some point the earth would would burn up from the waste heat emitted from all of the energy use. The optimists counter that we can have immaterial economic goods so production does not have to be tied to energy.

I would argue that gaining and maintaining knowledge requires a significant amount of energy. While computers make it look effortless to spreading knowledge, in fact every web page that is visited costs a little bit of energy. It is hard to see how we could create an ever more impressive virtual world without increasing energy costs in the real world. So for now I side with the realists!

Of course even if the growth does stop someday it is hard to know when it will stop. I have given up predicting when that will happen exactly. If I had to guess we might have some economic struggles in the short term, but over all keep with the exponential growth for a couple more decades.

If there are limits on growth, how do they work? Economic value depends on perception of value, but it is not clear to me how perception is related to physical quantities. How is energy related to economic transactions? How is knowledge, economic value, and information related?

 

Posted on
by

Diarrhea is definitely unpleasant, but how does it work physiologically?

What causes food and drink to pass through the system more quickly? Is the motion caused by mechanical action of the intestines, or could it be that the intestines somehow stop absorbing fluid? If they can turn absorption on and off, how does that happen?

The BRAT diet (Bananas, Rice, Applesauce, and Toast) is often recommended as a home remedy to diarrhea. The idea is that these bland foods are “easier” to digest than foods with a lot of fat, protein, or fiber. Why are some foods easier to digest than others? Is it related to the size of the food molecules, with small molecules more easily diffusing into the bloodstream?

Is diarrhea a response to fight against infection? Is it effective? How does it work?

Does diarrhea cause damage to the intestines? I could imagine that if stomach acid goes down into the intestines that it could damage all the little intestinal villi that are important in absorbing nutrients. I wonder if diarrhea could upset the microbiome as well.

Posted on
by

I’m hearing more and more that good posture is important for health and wellness. Doing a quick search I found several articles including one from Harvard Health touting the benefits of good posture. This article suggests exercises that are supposed to help with improving posture.

How realistic is the expectation that people can change their posture on their own? I see some people with excellent posture, and lots of others with their head hunched forward. Do some people just naturally have good posture? Are their people who have gone from terrible posture to good posture? How did they do it? What is their stories?

I am a believer that it is possible to improve posture through exercise and stretching. I think about people who do ballet, and they all seem to have extraordinary posture. Their training and exercises must play a role.

I also think about posture in terms of the structure of our bodies. There are ligaments holding the spine together and these ligaments actually support the loads on the back (the spine is a tensegrity structure). If the length of those ligaments changes then the curve of the spine will change. I think that exercises could slowly change the lengths of these ligaments and strengthen them so that the spine has the optimal curvature.

Still even if it is possible theoretically to improve your posture, how difficult will it be? Should we leave good posture to the dancers and figure skaters, or can we take on the task of aligning our bodies?

 

Posted on
by

I looked up the growth charts from the WHO which show how kids (boys in the figure below) grow from birth to 19 years of age. The curves are nice and smooth so it seems like you might be able to predict adult height based on the height as a 1 year old. But the charts only show the averages. How often do children change height percentiles? How common is it for kids to grow early and end up short? Or vice versa how common is it for kids to grow late but to end up on the tall end?

cht_lhfa_boys_z_0_5

Source: https://www.who.int/childgrowth/standards/cht_lhfa_boys_z_0_5.pdf?ua=1

cht_hfa_boys_z_5_19years

Source: https://www.who.int/growthref/cht_hfa_boys_z_5_19years.pdf?ua=1

Posted on
by

I am generalizing the scope of this blog from science and tech to things that I am interested in. I plan on tagging posts so that it will be reasonably easy to filter for what you are interested in. 

Today’s post is the start of a series on questions. Questions are powerful. I have been feeling dulled by my reflex to look up things on Google immediately on thinking up a question. I get quick answers, but fail really learn. I hope that by taking the time to write out the questions that I will learn and perhaps you will find it interesting too.

Q: What are the most common causes of death of 1 year olds?

As a parent of a 1 year old, I’m interested in learning both what makes my son healthy and what risks to avoid. The risks are especially hard, because something can be scary but very unlikely. So what are the top 10 causes of death for 1 year olds in the US?

I have some follow-up questions as well: What is the rate of deaths per year per capita? How likely is a child in this cohort of children to die from each of these causes? How has this child mortality changed over time?

Just trying to avoid survivorship bias.