Just over a year ago, I sat down to ponder how to continue learning with my graduated students, professional peers and the many curious minds I've been fortunate to share knowledge with. Lectures and seminars are wonderful, but we are so restricted by time and topic. Thinking of where to begin feels slightly overwhelming, especially as my first "brain dump" resulted in a list of 153 topics! So, their time will come, but I haven't been able to move past a little nerdy science mantra of mine. It's something I've always told my students... Structure equals function. This phrase has always motivated me to learn what I hope to share with you. For me, it's the perfect personal, and professional philosophy to start with.

Structure = Function. From the molecular level: learn the structures, and you will know their functions. With your body and health: build and fortify your structures (anatomy), and you will improve their function (physiology). With our projects, our time, or our habits to change: building structure (with understanding, strategies, tactics and planning) improves function (fulfilling goals or desired changes).

You may remember the little Latin headings I included last week. We have our first one this week.

Delibero (to weigh well and consider maturely).

Structure and Function of Glucose (Part 1).

So, we begin week 1 of Analyse with a single molecule, glucose, selected for its simplicity, ubiquity, controversy and absolute essentiality to our structure and function. Any discussion you have on glucose requires incredible context and a mature, healthy dose of delibero.

Generally, glucose is introduced to you as C6H12O6. A small chain of 6 carbon atoms, with 12 hydrogen atoms and 6 oxygen atoms bonded in a specific arrangement to this small carbon chain. Plants synthesise glucose via photosynthesis to store an energy source for their growth, health, and reproduction (fruits, grains, etc). All the carbon, hydrogen and oxygen needed is supplied by soil, water and the atmosphere. Some plants arrange many glucose units into strong, rope-like polymers to fortify and build their structure (bark, peel, husks, etc). Again, the structure reveals the function: glucose not arranged in large polymers provides easy and rapid access to energy (fruiting body, seed body), but glucose molecules bundled and coiled in their thousands provide robust structure and protection for plants and some animals (e.g., chitin in crustaceans, exoskeletons for insects).

Without question, the topic of glucose or sugar for human health is problematic, again because we humans prefer neat and tidy, this verses that, good versus bad answers to complex problems. When considering glucose recommendations and diet, we must consider:

• Developmental stage (infant vs child vs puberty vs fertile years vs middle age vs elder years)
• Physiological gender (male or female physiological needs at specific developmental stage, different again for pregnancy and menopause transition and andropause)
• Activity levels, regardless of age
• Presence of underlying conditions (chronic inflammation, convalescence and recovery) or metabolic dysregulation (this includes pre-diabetes, insulin resistance, type 2 diabetes, gout, non-alcoholic fatty liver disease (NAFLD), regardless of age. Yes, many of these present in children. Sadly, this is becoming more common.

Hence, we must attend to the unique person in front of us.

As a clinician, your patient education on glucose and diet may involve wide brushstroke recommendations. Other clients require re-education on the importance of glucose re-introduction into their diet. Without question, modern humanity has refined, adulterated and enhanced seasonal crops to provide foods that have sustained us, tempted us and damaged our health. The aim is not to malign glucose, but to appreciate the nuance, context, and biochemical intricacy of this vital molecule.

To have a deeper understanding of why excess glucose is problematic, we must recognise that it has a similar structure to 2 other monosaccharides (simple sugars): galactose (from lactose in animal milks) and fructose (fruits, some veggies, but mostly high fructose corn syrup, sugary foods and drinks). Glucose, galactose and fructose are all isomers of each other; same molecular formula (C6H12O6) but the atoms are arranged differently. Glucose and galactose are SO similar, they are almost identical. They are known as aldoses, as they both contain an aldehyde functional group. Fructose is a ketose: it is unlike the others, as it contains a ketone group, and no aldehyde group. Recall that -ose is the suffix telling us the molecule is a carbohydrate.

Ingested glucose is the preferred substrate for Glycolysis, the biochemical pathway sustained and refined by evolution to commence the process of extracting energy from carbohydrates. Glucose and glycolysis are vital for our survival, so much that evolution made the glycolysis pathway "penetrable", it is not a closed system. This allows galactose and fructose to be converted into glucose, almost like entering Glycolysis via a "side door". This side door preparation occurs in our liver (side note: our liver is SO important beyond 'detox' chats! It's so important for the metabolism of carbohydrate, lipids (fats) and proteins and 5 zillion other reactions that keep us alive, but I'm getting distracted). For galactose, the conversion to glucose is only 3 steps, via the Leloir pathway (most students and clinicians have never heard of this one, it occurs in the liver).

The similar structure of galactose and fructose to glucose means their conversion to glucose is rather simple. This is life-saving when we consider that living organisms need fuel and the energy extracted from it to keep us alive and healthy. But! Here is this clinical issue: their conversion to glucose means that galactose and fructose are both, eventually contributing to our blood glucose levels. This is not a problem when we are active and eating balanced amounts of carbohydrate from wholefood. It is a huge problem when we are not active and routinely eating and drinking junk.

Over the next few weeks, I'm offering a bit of a mini-series on glucose-galactose-fructose. Next week, we will take a closer look at fructose, how the structure of glucose imparts the perfect function for its vital role in energy (ATP) replenishment, plus some areas of human health where glucose actually serves a structural role outside of energy metabolism

Please know, the purpose of this week is multifaceted. I want to impart that glucose is essential. When we understand the biochemistry more, we recognise that our blood glucose level comes not only from the glucose we ingest, but also from the galactose and fructose we ingest. It also arises from the protein we eat, but let's save that for another day. If you are not a student or practitioner, that's OK! Understanding some structure and function on a deeper level will help you be so much more discerning and astute when it comes to your health and what you read or hear.

I get so excited and motivated by aha moments, nerdy light bulbs illuminating and sharing joy, care and understanding about science. It's such a wonderful discipline and understanding belongs to everyone. Thank you for being here. I need to be patient with myself, and I need to respect your time! I plan on being here for a long time, this is too long already. I'm still figuring out the best format as I go, audio is coming soon.... I'll be back next week.

Kind regards, and be well.

Annalies

I'm very grateful you choose to read and learn from my work interests. Let me know your questions. I read them all, doing my best to incorporate these into future issues and lectures. I don't take your time for granted. Thank you! If Analyse was recommended to you, and you're not a subscriber yet, please consider doing so below.

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