Nutritional Biochemistry – Why Nutrients Are Fundamental to Health and the Mechanism of Action of Some Key Nutrients

Nutritional biochemistry is the study of the molecular interactions between nutrients and the body, focusing on how dietary components influence physiological processes and overall health. Nutrients are fundamental to health because they serve as the building blocks for cellular structures, energy production, and the regulation of metabolic pathways. FROM WITHIN explores the importance of nutrients in maintaining health, the biochemical mechanisms by which they function, and the roles of key nutrients including vitamins, minerals, fatty acids, and amino acids.

The Importance of Nutrients in Health

Nutrients are essential for sustaining life and optimising health. They are classified into macronutrients (carbohydrates, proteins, and fats) and micronutrients (vitamins and minerals). Each nutrient plays a unique role in maintaining homeostasis, supporting growth, and preventing disease. For example, carbohydrates are the primary energy source for cells, while proteins are critical for tissue repair and enzyme function. Fats, on the other hand, are essential for cell membrane integrity and hormone synthesis (Gropper & Smith, 2021).

Micronutrients, though required in smaller amounts, are equally vital. Vitamins and minerals act as cofactors for enzymatic reactions, antioxidants, and signalling molecules. Deficiencies in these nutrients can lead to severe health consequences, such as scurvy (vitamin C deficiency), anaemia (iron deficiency), and osteoporosis (calcium and vitamin D deficiency) (National Institutes of Health [NIH], 2023).

The biochemical pathways influenced by nutrients are complex and interconnected. For instance, the metabolism of macronutrients generates energy in the form of adenosine triphosphate (ATP), which powers cellular processes. Micronutrients, such as B vitamins, are integral to these metabolic pathways, acting as coenzymes in reactions such glycolysis, the citric acid cycle, and oxidative phosphorylation (Berg et al., 2022).

Mechanisms of Action of Key Nutrients

1. Vitamin D: Calcium Homeostasis and Immune Function

Vitamin D is a fat-soluble vitamin that plays a critical role in calcium absorption and bone health. It is synthesised in the skin upon exposure to ultraviolet B (UVB) radiation and is also obtained from dietary sources. The active form of vitamin D, calcitriol (1,25-dihydroxyvitamin D3), binds to the vitamin D receptor (VDR) in the intestines, promoting the expression of calcium-binding proteins that enhance calcium absorption (Holick, 2020).

Beyond its role in bone health, vitamin D modulates immune function. It regulates the expression of genes involved in innate and adaptive immunity, reducing inflammation and enhancing pathogen defence. Research has shown that vitamin D deficiency is associated with increased susceptibility to infections and autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis (Aranow, 2019).

2. Omega-3 Fatty Acids: Anti-Inflammatory and Cardiovascular Benefits

Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential polyunsaturated fats found in fatty fish and flaxseeds. These fatty acids are incorporated into cell membranes, where they influence membrane fluidity and signalling pathways. EPA and DHA are precursors to specialised pro-resolving mediators (SPMs), which resolve inflammation and promote tissue repair (Calder, 2020).

Omega-3 fatty acids also reduce the risk of cardiovascular disease by lowering triglyceride levels, improving endothelial function, and reducing blood pressure. A meta-analysis by Abdelhamid et al. (2020) found that higher intake of omega-3 fatty acids was associated with a reduced risk of myocardial infarction and coronary heart disease.

3. Iron: Oxygen Transport and Cellular Respiration

Iron is a trace mineral essential for oxygen transport and cellular respiration. It is a component of haemoglobin, the protein in red blood cells that carries oxygen from the lungs to tissues, and myoglobin, which stores oxygen in muscles. Iron is also a cofactor for enzymes involved in ATP production, such as cytochrome c oxidase in the electron transport chain (Abbaspour et al., 2019).

Iron deficiency impairs oxygen delivery and energy production, leading to fatigue, weakness, and anaemia. Conversely, excess iron can generate reactive oxygen species (ROS), causing oxidative stress and tissue damage. Therefore, iron homeostasis is tightly regulated through mechanisms involving hepcidin, a hormone that controls iron absorption and distribution (Ganz, 2019).

4. Vitamin C: Antioxidant and Collagen Synthesis

Vitamin C (ascorbic acid) is a water-soluble vitamin with potent antioxidant properties. It scavenges free radicals, protecting cells from oxidative damage, and regenerates other antioxidants, such as vitamin E. Vitamin C is also a cofactor for enzymes involved in collagen synthesis, carnitine production, and neurotransmitter synthesis (Carr & Maggini, 2017).

Collagen, the most abundant protein in the body, is essential for skin, bone, and connective tissue integrity. Vitamin C deficiency impairs collagen synthesis, leading to scurvy, characterised by bleeding gums, joint pain, and poor wound healing. Additionally, vitamin C enhances iron absorption by reducing dietary iron to its more bioavailable ferrous form (Lynch & Cook, 2020).

5. Magnesium: Enzyme Cofactor and Muscle Function

Magnesium is a mineral involved in over 300 enzymatic reactions, including those related to energy metabolism, DNA synthesis, and muscle contraction. It acts as a cofactor for ATPase, the enzyme that hydrolyses ATP to release energy, and is required for the activity of kinases, which regulate signal transduction pathways (Volpe, 2020).

Magnesium also plays a role in maintaining cardiovascular health by regulating blood pressure and heart rhythm. Deficiency in magnesium is associated with muscle cramps, arrhythmias, and increased risk of hypertension and type 2 diabetes (DiNicolantonio et al., 2018).

The Interplay Between Nutrients and Chronic Disease

Nutrients not only prevent deficiency diseases but also play a role in reducing the risk of chronic diseases. For example, diets rich in fruits, vegetables, whole grains, and lean proteins are associated with a lower risk of obesity, type 2 diabetes, and cardiovascular disease. These foods provide a complex matrix of nutrients and bioactive compounds that work synergistically to promote health (Mozaffarian, 2020).

The Mediterranean diet, characterized by high intake of extra virgin olive oil, nuts, fish, and plant-based foods, is a prime example of a nutrient-dense dietary pattern. It has been shown to reduce inflammation, improve lipid profiles, and lower the risk of metabolic syndrome (Estruch et al., 2018). Similarly, the DASH (Dietary Approaches to Stop Hypertension) diet, which emphasises potassium, calcium, and magnesium-rich foods, effectively lowers blood pressure (Appel et al., 2020).

Nutritional biochemistry provides a framework for understanding how nutrients influence health at the molecular level. Nutrients are fundamental to maintaining physiological processes, from energy production to immune function and tissue repair. Key nutrients, such as vitamin D, omega-3 fatty acids, iron, vitamin C, and magnesium, exert their effects through specific biochemical mechanisms, highlighting the importance of a balanced and varied diet. As research continues to uncover the intricate relationships between nutrients and health, it is clear that nutrition plays a central role in preventing and managing chronic diseases. If you need support with how to optimise your health and wellbeing across the lifespan, please book an appointment with Joanna here.

References

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