The Most Important Protein to Slow Down Aging: Collagen, Sirtuins, and More

October 8, 2025 •

4 min read

According to a 2025 review in Nature, declining levels of the coenzyme NAD+ can impair cellular functions and accelerate age-related diseases. As NAD+ is crucial for activating sirtuin proteins, which play key roles in regulating metabolism and DNA repair, boosting these levels is a focal point of research into what is the most important protein to slow down aging. This article delves into the specific proteins, including collagen and sirtuins, that influence the aging process and how your diet can support their function.

Quick Summary

This article explains how different proteins and related amino acids affect the aging process. It details the roles of collagen and sirtuins, highlighting how dietary choices and specific supplements can influence their functions to support longevity and overall health as we age.

Key Points

Sirtuins are a family of proteins linked to longevity. They regulate metabolism, DNA repair, and inflammation, with their activity dependent on the coenzyme NAD+.
Collagen provides structural support for skin and joints. As its natural production declines with age, replenishing its amino acid building blocks through diet or supplements can support skin elasticity and hydration.
The mTOR pathway can accelerate cellular aging if overactive. Proteins from animal sources, particularly those high in methionine and BCAAs, can strongly activate this pathway, while plant-based proteins can modulate it.
A plant-forward diet is associated with increased longevity. Research suggests that prioritizing protein from legumes, nuts, and seeds over processed red meat may support healthier aging due to lower levels of methionine and saturated fat.
Older adults require higher protein intake to prevent sarcopenia. While plant-based protein is beneficial, older individuals may need to consume more protein overall, sometimes supplemented with whey, to preserve muscle mass.
A balanced diet is more important than any single 'most important' protein. A strategic combination of protein sources, rich in essential amino acids and supporting nutrients, is key to influencing multiple longevity pathways simultaneously.

Understanding the Complexities of Protein and Aging

While the search for a single "most important protein" is a simplification of a complex biological process, scientific research has highlighted several proteins with a significant impact on aging and longevity. Rather than one superstar molecule, a network of proteins works together to influence healthspan. Factors like cellular senescence, DNA repair, and mitochondrial function are all managed by specific proteins, and their efficiency declines with age.

The Role of Sirtuins in Cellular Longevity

Sirtuins are a family of proteins that act as a crucial link between metabolism, aging, and stress tolerance. Nicknamed the "longevity genes," sirtuins regulate key cellular functions, including DNA repair, inflammatory responses, and mitochondrial functions. Their activity depends on the coenzyme NAD+, which naturally declines with age. By managing cellular stress and promoting repair, sirtuins help protect cells from damage and delay age-related decline. Increasing sirtuin activity, whether through caloric restriction, exercise, or potential supplements like NAD+ precursors (e.g., NMN or NR), is a key focus for longevity research.

Collagen and its Impact on Visible Aging

When most people think of anti-aging, collagen is the first protein that comes to mind. As the body's most abundant protein, collagen provides structure, strength, and elasticity to skin, bones, and connective tissues. Unfortunately, the body's natural collagen production begins to decline after age 25, accelerating after menopause. This reduction contributes to wrinkles, sagging skin, and joint pain.

Eating a balanced diet rich in amino acids like glycine and proline, along with cofactors like vitamin C, is essential for natural collagen synthesis. While consuming collagen-rich foods like bone broth won't directly deliver intact collagen to your skin, it provides the necessary building blocks. Studies show that supplements containing hydrolyzed collagen peptides can improve skin hydration and elasticity.

The Double-Edged Sword of mTOR Signaling

Another critical protein-related pathway influencing aging is the mechanistic target of rapamycin complex 1 (mTORC1). As a central regulator of cell growth and metabolism, mTORC1 activity is triggered by factors including amino acids from dietary protein. While essential for muscle building and tissue repair, consistently high mTORC1 activity is linked to accelerated cellular aging.

Interestingly, some amino acids, particularly branched-chain amino acids (BCAAs) like leucine, activate mTORC1 more potently than others. This has led some longevity researchers to suggest that a balanced, plant-forward diet, which is naturally lower in BCAAs and methionine, might promote healthspan by moderating this signaling pathway. However, this needs to be balanced with the increased protein needs of older adults to prevent sarcopenia.

Plant-Based vs. Animal-Based Protein for Longevity

Debates continue over the optimal protein source for longevity. Observational studies suggest that a higher intake of plant-based protein, rich in fiber and antioxidants, is associated with a lower risk of mortality and better health outcomes. Animal protein, particularly red and processed meat, has been linked to higher risks of chronic diseases.

A Comparison of Protein Sources


Feature	Plant-Based Protein (Legumes, Nuts)	Animal-Based Protein (Meat, Dairy)
Methionine Content	Generally lower, which may inhibit mTOR signaling and promote longevity.	Higher, particularly in red meat, which can elevate mTOR and IGF-1 levels linked to aging.
Amino Acid Profile	Often "incomplete," lacking sufficient levels of some essential amino acids, requiring varied sources to ensure completeness.	Considered "complete," providing all essential amino acids in optimal ratios.
Associated Nutrients	Rich in fiber, antioxidants, and anti-inflammatory compounds.	Can be high in saturated fats and sodium, especially with processed meats.
Effect on IGF-1	Lower intake is associated with lower insulin-like growth factor (IGF-1) levels, a biomarker linked to accelerated aging.	Higher intake, especially in younger and middle-aged adults, is linked to higher IGF-1 levels.

Key Considerations for Protein and Longevity

Choosing the right proteins to slow aging is less about a single-minded focus and more about a strategic, balanced approach. For middle-aged adults, evidence suggests that prioritizing plant-based proteins may offer advantages related to lower methionine intake and associated anti-inflammatory benefits. However, adequate protein consumption is crucial, especially for older adults, to combat sarcopenia.

Therefore, a diet rich in diverse plant proteins, complemented by moderate amounts of high-quality animal sources like fish, aligns with longevity diets such as the Mediterranean and Longevity diets. Supplements like hydrolyzed collagen can offer targeted benefits for skin and joints, but should not replace whole-food protein sources.

Conclusion

No single protein is the magic bullet for slowing down aging. Instead, the most effective strategy is a nuanced approach that addresses multiple biological pathways. Supporting the body's natural collagen production, modulating the mTOR pathway, and replenishing NAD+ to activate sirtuins are all critical components of a longevity-focused diet. This requires a balanced intake of diverse, high-quality protein sources, with a strong emphasis on nutrient-rich plants and a varied whole-food diet, complemented by targeted supplements where needed. For personalized advice, consider consulting a registered dietitian or physician to optimize your nutritional intake for a longer, healthier life. For more information on dietary choices for longevity, visit the resource provided by the University of Florida's Aging & Geriatric Research.

Frequently Asked Questions

Eating collagen-rich foods provides amino acids, which are the building blocks your body needs to produce its own collagen. Your body cannot absorb whole collagen, but rather breaks it down into amino acids it can use for various purposes, including tissue repair and synthesis.

For middle-aged adults, studies suggest that higher plant protein intake is associated with lower mortality and better overall health outcomes. Plant proteins are rich in fiber and antioxidants and often lower in methionine, which may beneficially modulate longevity pathways like mTOR. However, older adults may have higher protein needs to combat sarcopenia, which can be met through a mix of high-quality sources.

Sirtuins are proteins that function as anti-aging genes by regulating key processes like DNA repair, metabolism, and inflammation. Their activity is dependent on NAD+, a coenzyme that declines with age, contributing to cellular dysfunction and age-related disease.

NAD+ levels can be supported through lifestyle choices like a healthy diet, regular exercise, and stress reduction. Consuming foods rich in NAD+ precursors, such as vitamin B3 (niacin), found in fish, chicken, and whole grains, can also help. Some supplements, like NMN and NR, are also marketed for this purpose, though more research is ongoing.

Yes, adequate protein intake is critical for older adults. The recommended dietary allowance may be too low, and experts suggest higher amounts (1.0 to 1.2 grams per kilogram of body weight) to counteract age-related muscle loss, known as sarcopenia.

Research indicates that hydrolyzed collagen peptides, which are more easily absorbed, can potentially improve skin hydration, elasticity, and reduce the appearance of wrinkles. However, it's important to remember that lifestyle factors like sun exposure, diet, and smoking also play a huge role in skin aging.

Excessive intake of processed and red meat can be a concern, as it's linked to increased inflammation and risk of chronic disease. A diet that is too low in protein in older age can contribute to sarcopenia and overall frailty. Finding the right balance of high-quality, varied protein sources is the best approach.