How Much Nutrition Are You Actually Absorbing After 40?

There's a question most people who eat well never think to ask.

Not what to eat. Not how much protein. Not which supplements to take.

The question is: once the food is in, how much of it is your body actually using?

It sounds like a small detail. It isn't.

How Much Nutrition Do You Actually Absorb From Food?

When you eat a meal, the nutrients it contains don't automatically become available to your body. First, they need to be broken down; proteins into amino acids, carbohydrates into simple sugars, fats into fatty acids. Those components then need to pass through the gut wall and into the bloodstream. Only at that point can your body put them to use.

That process is digestion and absorption and it is far from guaranteed to be efficient.

While macronutrients; protein, carbohydrates and fat, are generally absorbed efficiently by the body, the picture for micronutrients is more variable. A peer-reviewed analysis published in Frontiers in Nutrition (2025) confirms that micronutrient bioavailability can vary widely depending on the nutrient and its form, the food matrix, and individual physiological factors including age.¹ A framework study published in Advances in Nutrition similarly notes that current nutritional intake recommendations are based on estimated total nutrient content in foods — but the actual amount absorbed and utilised by the body can differ significantly from what is consumed.²

The efficiency of how your body processes food is one of the key variables in that equation.

Why Nutrient Absorption Changes After 40

If you are in your 40s or 50s, this matters more than it did a decade ago, and the reason is well documented.

Digestive function is not entirely static across a lifetime. Clinical observational studies published in peer-reviewed literature suggest that digestive function may begin to decline as early as the fifth decade of life.³ A peer-reviewed study in PubMed found that pepsin output, a key enzyme involved in protein digestion, was reduced by approximately 40% in older adults compared to younger groups, with age remaining a robust predictor of reduced pepsin output after adjustment for other variables.⁴ Observational studies have also suggested that pancreatic enzyme output may show decreased activity with older age.³

The result is not dramatic in the short term. You do not suddenly stop absorbing nutrients. But for some, the efficiency of how your body processes food can change, quietly, gradually, in ways that are easy to overlook. Over time, that efficiency gap can become meaningful.

The Three Mechanisms That Determine What You Absorb

There are three distinct factors that determine how much nutritional value your body extracts from food.

1. Digestive enzyme activity

Digestive enzymes are the tools your body uses to break food down into absorbable components. In certain conditions, reduced enzyme activity may affect how thoroughly this process occurs. Protease enzymes break down protein, lipase handles dietary fat, and amylase processes carbohydrates.⁶ Supporting enzyme activity is one approach to maintaining efficient digestion.

2. The gut environment

The small intestine is where the majority of nutrient absorption takes place — research in Nutrition for Consumers confirms that over 95% of macronutrients are absorbed there.⁷ The bacterial environment within the gut plays a significant role in how efficiently this process operates. A well-supported gut microbiome is associated with normalised gut function; peer-reviewed research published in Frontiers in Nutrition notes that gut microbiota can influence absorption processes and that probiotic supplementation may support a healthy gut environment.⁸

3. Bioavailability

Bioavailability refers to the proportion of a nutrient that is actually absorbed and utilised once consumed. It varies significantly by nutrient form, by what you eat alongside it, and by the physiological state of your digestive system.¹ Some compounds are known to actively enhance bioavailability: piperine, derived from black pepper, is among the most well-researched. Studies cited in the Journal of Restorative Medicine show that piperine can increase the absorption rate of specific nutrients (including Vitamin B6, beta-carotene and CoQ10) by between 30% and 60%, by stimulating amino acid transporters in the intestinal lining.⁹

These three factors can work together. Supporting them collectively may help maintain the efficiency of the absorption process.

What This Means If You Are Already Eating Well

Here is the consideration that tends to get overlooked.

If your diet is already dialled in; quality protein sources, whole foods, a considered supplement stack, then the absorption question matters more, not less. Someone eating inconsistently has larger adjustments to make. But when the fundamentals are solid and the habits are consistent, supporting how your body processes what you eat can add up considerably over time.

Small, repeated gains are how optimisation works. You do the fundamentals well, then you look at the details. For many people in their 40s and 50s who are already doing everything right, absorption efficiency is one of the details that has not been looked at.

Nutrient Optimiser: How It Supports the Absorption Gap

Nutrient Optimiser from Reflex Nutrition is a digestion and absorption formula built around the three mechanisms described above.

Each capsule combines:

• DigeZyme® — a clinically studied multi-enzyme complex, including protease, amylase and lipase, designed to support the breakdown of proteins, carbohydrates and dietary fats into their absorbable components. DigeZyme® is a patented, researched ingredient with its own published clinical literature.¹⁰
• LactoSpore® (Bacillus Coagulans MTCC 5856) — a well-studied probiotic strain. A randomised, double-blind, placebo-controlled study found LactoSpore® to be safe for consumption and associated with increases in beneficial gut bacteria.¹¹ LactoSpore® is supported by multiple published clinical trials.
• Bifidobacterium Bifidum, Lactobacillus Acidophilus and Lactobacillus Rhamnosus — three established, widely researched probiotic strains providing additional support to the gut environment where absorption takes place.
• BioPerine® — a patented black pepper extract standardised to a minimum of 95% piperine, the compound identified in peer-reviewed literature as a natural bioavailability enhancer.⁹ BioPerine® is one of the most studied bioavailability-enhancing ingredients available in supplement formulations.
• Vitamin B6 — contributing to normal protein and glycogen metabolism, as per the authorised health claim on the GB Nutrition and Health Claims Register.¹²

These are not generic commodity ingredients. DigeZyme®, LactoSpore® and BioPerine® are all independently patented, branded compounds with their own clinical research programmes. The formulation helps address all three mechanisms: enzyme activity, gut environment and bioavailability, in a single capsule taken with a meal.

Food supplement. Vitamin B6 contributes to normal protein and glycogen metabolism. Take 1 capsule with a meal, up to 3 times daily. Do not exceed the stated daily dose.

The Compounding Logic

No single meal determines an outcome. But across every meal, every day, the cumulative effect of consistently getting more from your food adds up in ways that matter over months and years.

You have already done the work — the diet, the training, the discipline of consistent habits. The question this product addresses is straightforward: are you getting the full return on that effort?

Same meals. Better return.

Shop Nutrient Optimiser — £15.26 | 90 servings | £0.16 per serving →

Frequently Asked Questions

Why does nutrient absorption decline with age?

After the age of 40, the body's production of digestive enzymes, including gastric pepsin and pancreatic enzymes may decrease. Clinical studies suggest pepsin output can decline by up to 40% with advancing age.³ This reduction in enzyme activity could mean food is broken down less thoroughly, which can affect how much nutritional value the body is able to extract from meals.

How much of what I eat does my body actually absorb?

It varies depending on the type of nutrient. Macronutrients such as protein, carbohydrates and fat are generally absorbed efficiently. For micronutrients (vitamins and minerals) bioavailability can vary more widely depending on the nutrient form, food source, and individual factors such as age and gut health.¹ Factors including enzyme activity, gut microbiome health and the form of specific nutrients all play a role.

What is bioavailability and why does it matter?

Bioavailability is the proportion of a nutrient that is absorbed and available for use by the body after consumption. A food or supplement can contain a nutrient on its label while delivering significantly less to your cells, depending on how well it is absorbed. Supporting bioavailability, through ingredients like piperine, can meaningfully increase the proportion of nutrients that reach the bloodstream.

What does Vitamin B6 do in Nutrient Optimiser?

Vitamin B6 contributes to normal protein and glycogen metabolism. This is an authorised health claim on the GB Nutrition and Health Claims Register.¹² In the context of a diet with regular protein intake, this contributes to how the body processes and utilises dietary protein.

What is BioPerine® and what does the research show?

BioPerine® is a patented extract of black pepper fruit standardised to a minimum of 95% piperine. Research published in peer-reviewed journals shows that piperine can increase absorption rates of certain nutrients, including Vitamin B6, by 30–60%, by stimulating amino acid transporters in the intestinal lining and inhibiting enzymes that would otherwise metabolise nutrients before absorption.⁹

Is Nutrient Optimiser a medicine?

No. Nutrient Optimiser is a food supplement. It is not intended to diagnose, treat, cure or prevent any disease or medical condition. If you have a health condition or are taking medication, consult your GP before use.

References

1. Pereira, A.C. et al. (2025). Micronutrient bioavailability: concepts, influencing factors, and strategies for improvement. Frontiers in Nutrition / PMC. Available at: pmc.ncbi.nlm.nih.gov/articles/PMC12673670
2. King, J.C. et al. (2022). Framework for Developing Prediction Equations for Estimating the Absorption and Bioavailability of Nutrients from Foods. Advances in Nutrition / PMC. Available at: ncbi.nlm.nih.gov/pmc/articles/PMC12361767
3. Adler, G. et al. (2024). The Effects of a Microbial Enzyme Mixture on Macronutrient Hydrolysis in a Static Simulation of Oro-Gastric Digestion That Models Human Digestive Senescence. PMC. Available at: ncbi.nlm.nih.gov/pmc/articles/PMC11941177
4. Katelaris, P.H. et al. (1993). Effects of aging and gastritis on gastric acid and pepsin secretion in humans: a prospective study. PubMed. Available at: pubmed.ncbi.nlm.nih.gov/8612992
5. Anaya-Muñoz, V.H. et al. (2025). Age-Related Decline of Gastric Secretion: Facts and Controversies. PMC. Available at: pmc.ncbi.nlm.nih.gov/articles/PMC12292447
6. ScienceDirect. (2021). Digestion and Absorption. Available at: sciencedirect.com
7. University of North Texas. Digestion and Absorption of Nutrients — Nutrition for Consumers. Available at: openbooks.library.unt.edu
8. Pereira, A.C. et al. (2025). Micronutrient bioavailability: concepts, influencing factors, and strategies for improvement. Frontiers in Nutrition / PMC. Available at: pmc.ncbi.nlm.nih.gov/articles/PMC12673670
9. Restorative Medicine. Piperine, Black Pepper (Piper nigrum). Available at: restorativemedicine.org
10. Majeed, M. et al. (2018). Evaluation of the safety and efficacy of a multienzyme complex in patients with functional dyspepsia: A randomized, double-blind, placebo-controlled study. Journal of Medicinal Foods, 21(9), 912–921.
11. Majeed, M. et al. (2023). Probiotic modulation of gut microbiota by Bacillus coagulans MTCC 5856 in healthy subjects: A randomized, double-blind, placebo-control study. PMC. Available at: ncbi.nlm.nih.gov/pmc/articles/PMC10194586
12. UK Government. Great Britain Nutrition and Health Claims (NHC) Register. Available at: gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register

This article is for informational purposes only and does not constitute medical advice. Nutrient Optimiser is a food supplement and is not intended to diagnose, treat, cure or prevent any disease. Food supplements should be used alongside a varied, balanced diet and healthy lifestyle, not as a substitute for either. If you are pregnant, breastfeeding, taking medication or have a medical condition, consult your GP before use. Keep out of reach of children.