At what age do older people start to smell? Understanding nonenal

Research from the Monell Chemical Senses Center indicates that the distinctive 'aging odor' is identifiable by others in individuals aged 75 and older, though the responsible molecule, 2-nonenal, can appear as early as age 40. Exploring at what age do older people start to smell involves understanding these natural, age-related changes rather than issues with hygiene.

Quick Summary

The distinct scent associated with aging is primarily due to a compound called 2-nonenal, which the body can begin producing around age 40 and increases with time. This occurs from the oxidative breakdown of fatty acids on the skin's surface and is a normal part of the aging process, not a hygiene problem.

Key Points

• Not a Hygiene Issue: The distinctive 'aging odor' is a natural biological process, not caused by poor hygiene, and is tied to a specific compound called 2-nonenal.

• Starts Around 40: While most noticeable later in life, the body's production of 2-nonenal can increase from around age 40, though its intensity varies.

• Caused by Oxidized Fatty Acids: Nonenal is a byproduct of the oxidative breakdown of omega-7 unsaturated fatty acids on the skin, a process that increases as skin's antioxidant defenses decline with age.

• Non-Water Soluble: The culprit compound, 2-nonenal, is not easily removed with regular soap and water, which is why specialized cleansing and laundry methods are often required for effective management.

• Influenced by Many Factors: Hormonal changes, diet, metabolism, certain medications, and chronic health conditions can all influence and potentially intensify age-related odor.

• Manageable with Targeted Care: Strategies like using nonenal-neutralizing soaps, improving ventilation, and adjusting laundry practices can help manage and reduce the odor.

The Science Behind the 'Aging Odor'

Contrary to popular myths, the change in body odor with age is a natural biological phenomenon and not a result of poor hygiene. The scent is scientifically attributed to a chemical compound known as 2-nonenal. This aldehyde is produced on the skin's surface and is a byproduct of the oxidative degradation of omega-7 unsaturated fatty acids. A 2001 study published in the Journal of Investigative Dermatology was among the first to identify 2-nonenal as a key component of this age-related body odor.

How Nonenal is Produced

The process begins in the skin's sebaceous glands, which produce and secrete natural oils. As we age, hormonal shifts can alter the composition of these fatty acids. Specifically, the production of omega-7 unsaturated fatty acids increases, while the skin's natural antioxidant protection, which normally combats oxidative stress, decreases. This combination leads to the accelerated oxidation of the omega-7 fatty acids when exposed to air. The result of this chemical reaction is the formation of 2-nonenal, which has a distinct greasy, grassy, and sometimes musty odor.

The Age of Onset

While nonenal is most noticeable in individuals in their 70s and 80s, its production can begin much earlier. Some sources indicate that the increase in nonenal can start around age 40, making the scent a factor in middle age for some people. The intensity and specific characteristics of the scent can also vary widely from person to person, influenced by genetics, diet, and overall health. Not everyone experiences the scent to the same degree, and in some cases, it may not be present at all.

Factors Influencing Age-Related Body Odor

Beyond the primary cause of nonenal production, several other factors contribute to changes in body odor with age. Understanding these can provide a more complete picture of why and how body scent shifts over a lifetime.

Hormonal Shifts

For women, hormonal fluctuations during menopause can significantly impact body odor. Decreasing estrogen levels can affect sweat production and skin composition, leading to a more noticeable or different scent. Similarly, men experience gradual hormonal changes that can influence sebum and sweat composition over time.

Diet and Metabolism

As our metabolism slows and dietary habits change, so can our body's scent. Foods with strong, volatile compounds, like garlic, onions, or certain spices, can linger longer in the body and be released through sweat. A slower digestive system means these compounds are processed differently, potentially intensifying their effect on body odor. Proper hydration is also key, as drinking plenty of water can help flush out toxins and dilute odor-causing compounds.

Health Conditions and Medications

Certain chronic health conditions common in older adults can alter body scent. Examples include:

• Diabetes: Poorly controlled blood sugar can cause a fruity or acetone-like smell.
• Kidney or Liver Disease: The body’s inability to properly filter waste products can lead to a urine-like or ammonia-like odor.
• Skin Conditions: Eczema and dermatitis can change the skin's microbiome and impact odor.
• Medications: Many medications, from thyroid drugs to opioids, can cause changes in body odor as a side effect.

Comparison: Age-Related Odor vs. Typical Sweat Odor

Feature	Age-Related Odor (Nonenal)	Typical Sweat Odor
Cause	Oxidative degradation of omega-7 fatty acids on the skin surface	Bacteria breaking down sweat produced by apocrine glands
Scent Profile	Greasy, grassy, musty	Pungent, acrid
Washability	Not easily washed off with regular soap, as nonenal is not water-soluble	Washes off easily with regular soap
Affected Areas	Whole body, but can accumulate on fabrics and bedding	Concentrated in areas with apocrine glands, like armpits and groin
Timing	Increases from around age 40 and onwards	Starts during puberty and fluctuates with hormones and stress

Management Strategies for Age-Related Odor

While nonenal is a natural part of aging and not preventable, its effects can be managed effectively. The key is to use targeted strategies beyond standard hygiene, as nonenal is not water-soluble.

1. Use specialized soaps: Some products, particularly those from Japan that target kareishuu (age-related smell), are specifically formulated to break down 2-nonenal. Look for soaps containing Japanese persimmon extract, or other nonenal-neutralizing ingredients. Using antibacterial soap can also help manage the bacteria that contribute to odor.
2. Exfoliate gently: Regular, gentle exfoliation using a soft cloth or scrub helps remove the dead skin cells where oxidized lipids can accumulate.
3. Enhance laundry practices: Since nonenal can cling to fabrics, it's important to use laundry methods that combat it. Adding vinegar to the rinse cycle or using laundry supplements designed to cut grease and eliminate odors can be effective.
4. Improve home ventilation: Airing out living spaces by opening windows and using fans can prevent odors from becoming concentrated in enclosed areas. Air purifiers with activated carbon filters can also help absorb lingering smells.
5. Adjust your diet: Staying well-hydrated and reducing the intake of foods with strong, odor-causing compounds can help. Some studies suggest consuming green tea or antioxidants may also help from the inside out.

For more detailed information on the scientific breakdown of 2-nonenal, you can consult studies like this one from the Journal of Investigative Dermatology.

Conclusion

Changes in body odor are a normal and natural part of the human aging process, primarily driven by the chemical compound 2-nonenal. This phenomenon is not linked to poor hygiene but to a biological shift in skin composition that can begin as early as age 40. By understanding the root causes and implementing specific management strategies—such as using specialized soaps, optimizing laundry habits, and improving home ventilation—it is possible to address and minimize the effects of age-related body odor. Focusing on a compassionate, informed approach can help maintain dignity and comfort for everyone affected by this common occurrence.

Frequently Asked Questions

At what age do older people start to smell differently?

Scientific studies indicate that the chemical compound responsible for the 'aging odor' can start to appear in individuals as early as age 40, though it typically becomes more pronounced in later decades, such as after age 75.

What is the cause of the distinct 'aging odor'?

The specific scent is caused by a molecule called 2-nonenal. It is created when omega-7 unsaturated fatty acids on the skin surface undergo an oxidative breakdown, a process that accelerates with age.

Is the 'old people smell' a sign of poor hygiene?

No, the change in body odor is not a result of poor hygiene. It is a natural biological change in body chemistry that happens as we age, specifically involving the production of 2-nonenal.

What can be done to minimize age-related odor?

Since nonenal is not water-soluble, managing the odor involves more than just regular soap. Effective strategies include using nonenal-neutralizing soaps (like Japanese persimmon soap), improving home ventilation, adjusting laundry practices, and maintaining a healthy diet and hydration.

Can diet affect age-related body odor?

Yes, diet plays a role. As metabolism slows, the body processes certain compounds differently. Diets high in strong-smelling foods like garlic or certain spices can affect overall body odor. Hydration is also important for flushing out odor-causing compounds.

Can certain medical conditions cause a change in odor?

Yes, certain health issues like diabetes, kidney disease, and liver problems can alter body odor. Additionally, some medications common among older adults can also be a contributing factor.

Why doesn't regular bathing remove nonenal odor?

Nonenal is a lipid-based compound, meaning it is not water-soluble. While bathing helps remove regular sweat and bacteria, it's not always effective against the specific fatty acid buildup associated with nonenal, requiring more targeted cleansing methods.